The perf_event_aux() function iterates all PMUs and all events in
their respective per-CPU contexts to find the events to deliver
side-band records to.
For example, the brk test case in lkp triggers many mmap() operations,
which, if we're also running perf, results in many perf_event_aux()
invocations.
If we enable uncore PMU support (even when uncore events are not used),
dozens of uncore PMUs will be iterated, which can significantly
decrease brk_test's throughput.
For example, the brk throughput:
without uncore PMUs: 2647573 ops_per_sec
with uncore PMUs: 1768444 ops_per_sec
... a 33% reduction.
To get at the per-CPU events that need side-band records, this patch
puts these events on a per-CPU list, this avoids iterating the PMUs
and any events that do not need side-band records.
Per task events are unchanged to avoid extra overhead on the context
switch paths.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: Huang, Ying <ying.huang@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1458757477-3781-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Additionally to being able to control the system wide maximum depth via
/proc/sys/kernel/perf_event_max_stack, now we are able to ask for
different depths per event, using perf_event_attr.sample_max_stack for
that.
This uses an u16 hole at the end of perf_event_attr, that, when
perf_event_attr.sample_type has the PERF_SAMPLE_CALLCHAIN, if
sample_max_stack is zero, means use perf_event_max_stack, otherwise
it'll be bounds checked under callchain_mutex.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/n/tip-kolmn1yo40p7jhswxwrc7rrd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf updates from Ingo Molnar:
"Mostly tooling and PMU driver fixes, but also a number of late updates
such as the reworking of the call-chain size limiting logic to make
call-graph recording more robust, plus tooling side changes for the
new 'backwards ring-buffer' extension to the perf ring-buffer"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
perf record: Read from backward ring buffer
perf record: Rename variable to make code clear
perf record: Prevent reading invalid data in record__mmap_read
perf evlist: Add API to pause/resume
perf trace: Use the ptr->name beautifier as default for "filename" args
perf trace: Use the fd->name beautifier as default for "fd" args
perf report: Add srcline_from/to branch sort keys
perf evsel: Record fd into perf_mmap
perf evsel: Add overwrite attribute and check write_backward
perf tools: Set buildid dir under symfs when --symfs is provided
perf trace: Only auto set call-graph to "dwarf" when syscalls are being traced
perf annotate: Sort list of recognised instructions
perf annotate: Fix identification of ARM blt and bls instructions
perf tools: Fix usage of max_stack sysctl
perf callchain: Stop validating callchains by the max_stack sysctl
perf trace: Fix exit_group() formatting
perf top: Use machine->kptr_restrict_warned
perf trace: Warn when trying to resolve kernel addresses with kptr_restrict=1
perf machine: Do not bail out if not managing to read ref reloc symbol
perf/x86/intel/p4: Trival indentation fix, remove space
...
Pull networking updates from David Miller:
"Highlights:
1) Support SPI based w5100 devices, from Akinobu Mita.
2) Partial Segmentation Offload, from Alexander Duyck.
3) Add GMAC4 support to stmmac driver, from Alexandre TORGUE.
4) Allow cls_flower stats offload, from Amir Vadai.
5) Implement bpf blinding, from Daniel Borkmann.
6) Optimize _ASYNC_ bit twiddling on sockets, unless the socket is
actually using FASYNC these atomics are superfluous. From Eric
Dumazet.
7) Run TCP more preemptibly, also from Eric Dumazet.
8) Support LED blinking, EEPROM dumps, and rxvlan offloading in mlx5e
driver, from Gal Pressman.
9) Allow creating ppp devices via rtnetlink, from Guillaume Nault.
10) Improve BPF usage documentation, from Jesper Dangaard Brouer.
11) Support tunneling offloads in qed, from Manish Chopra.
12) aRFS offloading in mlx5e, from Maor Gottlieb.
13) Add RFS and RPS support to SCTP protocol, from Marcelo Ricardo
Leitner.
14) Add MSG_EOR support to TCP, this allows controlling packet
coalescing on application record boundaries for more accurate
socket timestamp sampling. From Martin KaFai Lau.
15) Fix alignment of 64-bit netlink attributes across the board, from
Nicolas Dichtel.
16) Per-vlan stats in bridging, from Nikolay Aleksandrov.
17) Several conversions of drivers to ethtool ksettings, from Philippe
Reynes.
18) Checksum neutral ILA in ipv6, from Tom Herbert.
19) Factorize all of the various marvell dsa drivers into one, from
Vivien Didelot
20) Add VF support to qed driver, from Yuval Mintz"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1649 commits)
Revert "phy dp83867: Fix compilation with CONFIG_OF_MDIO=m"
Revert "phy dp83867: Make rgmii parameters optional"
r8169: default to 64-bit DMA on recent PCIe chips
phy dp83867: Make rgmii parameters optional
phy dp83867: Fix compilation with CONFIG_OF_MDIO=m
bpf: arm64: remove callee-save registers use for tmp registers
asix: Fix offset calculation in asix_rx_fixup() causing slow transmissions
switchdev: pass pointer to fib_info instead of copy
net_sched: close another race condition in tcf_mirred_release()
tipc: fix nametable publication field in nl compat
drivers: net: Don't print unpopulated net_device name
qed: add support for dcbx.
ravb: Add missing free_irq() calls to ravb_close()
qed: Remove a stray tab
net: ethernet: fec-mpc52xx: use phy_ethtool_{get|set}_link_ksettings
net: ethernet: fec-mpc52xx: use phydev from struct net_device
bpf, doc: fix typo on bpf_asm descriptions
stmmac: hardware TX COE doesn't work when force_thresh_dma_mode is set
net: ethernet: fs-enet: use phy_ethtool_{get|set}_link_ksettings
net: ethernet: fs-enet: use phydev from struct net_device
...
The perf_sample->ip_callchain->nr value includes all the entries in the
ip_callchain->ip[] array, real addresses and PERF_CONTEXT_{KERNEL,USER,etc},
while what the user expects is that what is in the kernel.perf_event_max_stack
sysctl or in the upcoming per event perf_event_attr.sample_max_stack knob be
honoured in terms of IP addresses in the stack trace.
So allocate a bunch of extra entries for contexts, and do the accounting
via perf_callchain_entry_ctx struct members.
A new sysctl, kernel.perf_event_max_contexts_per_stack is also
introduced for investigating possible bugs in the callchain
implementation by some arch.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/n/tip-3b4wnqk340c4sg4gwkfdi9yk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We need have different helpers to account how many contexts we have in
the sample and for real addresses, so do it now as a prep patch, to
ease review.
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-q964tnyuqrxw5gld18vizs3c@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We will use it to count how many addresses are in the entry->ip[] array,
excluding PERF_CONTEXT_{KERNEL,USER,etc} entries, so that we can really
return the number of entries specified by the user via the relevant
sysctl, kernel.perf_event_max_contexts, or via the per event
perf_event_attr.sample_max_stack knob.
This way we keep the perf_sample->ip_callchain->nr meaning, that is the
number of entries, be it real addresses or PERF_CONTEXT_ entries, while
honouring the max_stack knobs, i.e. the end result will be max_stack
entries if we have at least that many entries in a given stack trace.
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-s8teto51tdqvlfhefndtat9r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This makes perf_callchain_{user,kernel}() receive the max stack
as context for the perf_callchain_entry, instead of accessing
the global sysctl_perf_event_max_stack.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/n/tip-kolmn1yo40p7jhswxwrc7rrd@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Commit:
2665784850 ("perf/core: Verify we have a single perf_hw_context PMU")
forcefully prevents multiple PMUs from sharing perf_hw_context, as this
generally doesn't make sense. It is a common bug for uncore PMUs to
use perf_hw_context rather than perf_invalid_context, which this detects.
However, systems exist with heterogeneous CPUs (and hence heterogeneous
HW PMUs), for which sharing perf_hw_context is necessary, and possible
in some limited cases.
To make this work we have to perform some gymnastics, as we did in these
commits:
66eb579e66 ("perf: allow for PMU-specific event filtering")
c904e32a69 ("arm: perf: filter unschedulable events")
To allow those systems to work, we must allow PMUs for heterogeneous
CPUs to share perf_hw_context, though we must still disallow sharing
otherwise to detect the common misuse of perf_hw_context.
This patch adds a new PERF_PMU_CAP_HETEROGENEOUS_CPUS for this, updates
the core logic to account for this, and makes use of it in the arm_pmu
code that is used for systems with heterogeneous CPUs. Comments are
added to make the rationale clear and hopefully avoid accidental abuse.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20160426103346.GA20836@leverpostej
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Many instruction tracing PMUs out there support address range-based
filtering, which would, for example, generate trace data only for a
given range of instruction addresses, which is useful for tracing
individual functions, modules or libraries. Other PMUs may also
utilize this functionality to allow filtering to or filtering out
code at certain address ranges.
This patch introduces the interface for userspace to specify these
filters and for the PMU drivers to apply these filters to hardware
configuration.
The user interface is an ASCII string that is passed via an ioctl()
and specifies (in the form of an ASCII string) address ranges within
certain object files or within kernel. There is no special treatment
for kernel modules yet, but it might be a worthy pursuit.
The PMU driver interface basically adds two extra callbacks to the
PMU driver structure, one of which validates the filter configuration
proposed by the user against what the hardware is actually capable of
doing and the other one translates hardware-independent filter
configuration into something that can be programmed into the
hardware.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/1461771888-10409-6-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The default remains 127, which is good for most cases, and not even hit
most of the time, but then for some cases, as reported by Brendan, 1024+
deep frames are appearing on the radar for things like groovy, ruby.
And in some workloads putting a _lower_ cap on this may make sense. One
that is per event still needs to be put in place tho.
The new file is:
# cat /proc/sys/kernel/perf_event_max_stack
127
Chaging it:
# echo 256 > /proc/sys/kernel/perf_event_max_stack
# cat /proc/sys/kernel/perf_event_max_stack
256
But as soon as there is some event using callchains we get:
# echo 512 > /proc/sys/kernel/perf_event_max_stack
-bash: echo: write error: Device or resource busy
#
Because we only allocate the callchain percpu data structures when there
is a user, which allows for changing the max easily, its just a matter
of having no callchain users at that point.
Reported-and-Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/20160426002928.GB16708@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch introduces 'write_backward' bit to perf_event_attr, which
controls the direction of a ring buffer. After set, the corresponding
ring buffer is written from end to beginning. This feature is design to
support reading from overwritable ring buffer.
Ring buffer can be created by mapping a perf event fd. Kernel puts event
records into ring buffer, user tooling like perf fetch them from
address returned by mmap(). To prevent racing between kernel and tooling,
they communicate to each other through 'head' and 'tail' pointers.
Kernel maintains 'head' pointer, points it to the next free area (tail
of the last record). Tooling maintains 'tail' pointer, points it to the
tail of last consumed record (record has already been fetched). Kernel
determines the available space in a ring buffer using these two
pointers to avoid overwrite unfetched records.
By mapping without 'PROT_WRITE', an overwritable ring buffer is created.
Different from normal ring buffer, tooling is unable to maintain 'tail'
pointer because writing is forbidden. Therefore, for this type of ring
buffers, kernel overwrite old records unconditionally, works like flight
recorder. This feature would be useful if reading from overwritable ring
buffer were as easy as reading from normal ring buffer. However,
there's an obscure problem.
The following figure demonstrates a full overwritable ring buffer. In
this figure, the 'head' pointer points to the end of last record, and a
long record 'E' is pending. For a normal ring buffer, a 'tail' pointer
would have pointed to position (X), so kernel knows there's no more
space in the ring buffer. However, for an overwritable ring buffer,
kernel ignore the 'tail' pointer.
(X) head
. |
. V
+------+-------+----------+------+---+
|A....A|B.....B|C........C|D....D| |
+------+-------+----------+------+---+
Record 'A' is overwritten by event 'E':
head
|
V
+--+---+-------+----------+------+---+
|.E|..A|B.....B|C........C|D....D|E..|
+--+---+-------+----------+------+---+
Now tooling decides to read from this ring buffer. However, none of these
two natural positions, 'head' and the start of this ring buffer, are
pointing to the head of a record. Even the full ring buffer can be
accessed by tooling, it is unable to find a position to start decoding.
The first attempt tries to solve this problem AFAIK can be found from
[1]. It makes kernel to maintain 'tail' pointer: updates it when ring
buffer is half full. However, this approach introduces overhead to
fast path. Test result shows a 1% overhead [2]. In addition, this method
utilizes no more tham 50% records.
Another attempt can be found from [3], which allows putting the size of
an event at the end of each record. This approach allows tooling to find
records in a backward manner from 'head' pointer by reading size of a
record from its tail. However, because of alignment requirement, it
needs 8 bytes to record the size of a record, which is a huge waste. Its
performance is also not good, because more data need to be written.
This approach also introduces some extra branch instructions to fast
path.
'write_backward' is a better solution to this problem.
Following figure demonstrates the state of the overwritable ring buffer
when 'write_backward' is set before overwriting:
head
|
V
+---+------+----------+-------+------+
| |D....D|C........C|B.....B|A....A|
+---+------+----------+-------+------+
and after overwriting:
head
|
V
+---+------+----------+-------+---+--+
|..E|D....D|C........C|B.....B|A..|E.|
+---+------+----------+-------+---+--+
In each situation, 'head' points to the beginning of the newest record.
From this record, tooling can iterate over the full ring buffer and fetch
records one by one.
The only limitation that needs to be considered is back-to-back reading.
Due to the non-deterministic of user programs, it is impossible to ensure
the ring buffer keeps stable during reading. Consider an extreme situation:
tooling is scheduled out after reading record 'D', then a burst of events
come, eat up the whole ring buffer (one or multiple rounds). When the
tooling process comes back, reading after 'D' is incorrect now.
To prevent this problem, we need to find a way to ensure the ring buffer
is stable during reading. ioctl(PERF_EVENT_IOC_PAUSE_OUTPUT) is
suggested because its overhead is lower than
ioctl(PERF_EVENT_IOC_ENABLE).
By carefully verifying 'header' pointer, reader can avoid pausing the
ring-buffer. For example:
/* A union of all possible events */
union perf_event event;
p = head = perf_mmap__read_head();
while (true) {
/* copy header of next event */
fetch(&event.header, p, sizeof(event.header));
/* read 'head' pointer */
head = perf_mmap__read_head();
/* check overwritten: is the header good? */
if (!verify(sizeof(event.header), p, head))
break;
/* copy the whole event */
fetch(&event, p, event.header.size);
/* read 'head' pointer again */
head = perf_mmap__read_head();
/* is the whole event good? */
if (!verify(event.header.size, p, head))
break;
p += event.header.size;
}
However, the overhead is high because:
a) In-place decoding is not safe.
Copying-verifying-decoding is required.
b) Fetching 'head' pointer requires additional synchronization.
(From Alexei Starovoitov:
Even when this trick works, pause is needed for more than stability of
reading. When we collect the events into overwrite buffer we're waiting
for some other trigger (like all cpu utilization spike or just one cpu
running and all others are idle) and when it happens the buffer has
valuable info from the past. At this point new events are no longer
interesting and buffer should be paused, events read and unpaused until
next trigger comes.)
This patch utilizes event's default overflow_handler introduced
previously. perf_event_output_backward() is created as the default
overflow handler for backward ring buffers. To avoid extra overhead to
fast path, original perf_event_output() becomes __perf_event_output()
and marked '__always_inline'. In theory, there's no extra overhead
introduced to fast path.
Performance testing:
Calling 3000000 times of 'close(-1)', use gettimeofday() to check
duration. Use 'perf record -o /dev/null -e raw_syscalls:*' to capture
system calls. In ns.
Testing environment:
CPU : Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz
Kernel : v4.5.0
MEAN STDVAR
BASE 800214.950 2853.083
PRE1 2253846.700 9997.014
PRE2 2257495.540 8516.293
POST 2250896.100 8933.921
Where 'BASE' is pure performance without capturing. 'PRE1' is test
result of pure 'v4.5.0' kernel. 'PRE2' is test result before this
patch. 'POST' is test result after this patch. See [4] for the detailed
experimental setup.
Considering the stdvar, this patch doesn't introduce performance
overhead to the fast path.
[1] http://lkml.iu.edu/hypermail/linux/kernel/1304.1/04584.html
[2] http://lkml.iu.edu/hypermail/linux/kernel/1307.1/00535.html
[3] http://lkml.iu.edu/hypermail/linux/kernel/1512.0/01265.html
[4] http://lkml.kernel.org/g/56F89DCD.1040202@huawei.com
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: <acme@kernel.org>
Cc: <pi3orama@163.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1459865478-53413-1-git-send-email-wangnan0@huawei.com
[ Fixed the changelog some more. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
split allows to move expensive update of 'struct trace_entry' to later phase.
Repurpose unused 1st argument of perf_tp_event() to indicate event type.
While splitting use temp variable 'rctx' instead of '*rctx' to avoid
unnecessary loads done by the compiler due to -fno-strict-aliasing
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
avoid memset in perf_fetch_caller_regs, since it's the critical path of all tracepoints.
It's called from perf_sw_event_sched, perf_event_task_sched_in and all of perf_trace_##call
with this_cpu_ptr(&__perf_regs[..]) which are zero initialized by perpcu init logic and
subsequent call to perf_arch_fetch_caller_regs initializes the same fields on all archs,
so we can safely drop memset from all of the above cases and move it into
perf_ftrace_function_call that calls it with stack allocated pt_regs.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Set a default event->overflow_handler in perf_event_alloc() so don't
need to check event->overflow_handler in __perf_event_overflow().
Following commits can give a different default overflow_handler.
Initial idea comes from Peter:
http://lkml.kernel.org/r/20130708121557.GA17211@twins.programming.kicks-ass.net
Since the default value of event->overflow_handler is not NULL, existing
'if (!overflow_handler)' checks need to be changed.
is_default_overflow_handler() is introduced for this.
No extra performance overhead is introduced into the hot path because in the
original code we still need to read this handler from memory. A conditional
branch is avoided so actually we remove some instructions.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <pi3orama@163.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1459147292-239310-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf fixes from Ingo Molnar:
"This tree contains various perf fixes on the kernel side, plus three
hw/event-enablement late additions:
- Intel Memory Bandwidth Monitoring events and handling
- the AMD Accumulated Power Mechanism reporting facility
- more IOMMU events
... and a final round of perf tooling updates/fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
perf llvm: Use strerror_r instead of the thread unsafe strerror one
perf llvm: Use realpath to canonicalize paths
perf tools: Unexport some methods unused outside strbuf.c
perf probe: No need to use formatting strbuf method
perf help: Use asprintf instead of adhoc equivalents
perf tools: Remove unused perf_pathdup, xstrdup functions
perf tools: Do not include stringify.h from the kernel sources
tools include: Copy linux/stringify.h from the kernel
tools lib traceevent: Remove redundant CPU output
perf tools: Remove needless 'extern' from function prototypes
perf tools: Simplify die() mechanism
perf tools: Remove unused DIE_IF macro
perf script: Remove lots of unused arguments
perf thread: Rename perf_event__preprocess_sample_addr to thread__resolve
perf machine: Rename perf_event__preprocess_sample to machine__resolve
perf tools: Add cpumode to struct perf_sample
perf tests: Forward the perf_sample in the dwarf unwind test
perf tools: Remove misplaced __maybe_unused
perf list: Fix documentation of :ppp
perf bench numa: Fix assertion for nodes bitfield
...
Introduce an AMD accumlated power reporting mechanism for the Family
15h, Model 60h processor that can be used to calculate the average
power consumed by a processor during a measurement interval. The
feature support is indicated by CPUID Fn8000_0007_EDX[12].
This feature will be implemented both in hwmon and perf. The current
design provides one event to report per package/processor power
consumption by counting each compute unit power value.
Here the gory details of how the computation is done:
* Tsample: compute unit power accumulator sample period
* Tref: the PTSC counter period (PTSC: performance timestamp counter)
* N: the ratio of compute unit power accumulator sample period to the
PTSC period
* Jmax: max compute unit accumulated power which is indicated by
MSR_C001007b[MaxCpuSwPwrAcc]
* Jx/Jy: compute unit accumulated power which is indicated by
MSR_C001007a[CpuSwPwrAcc]
* Tx/Ty: the value of performance timestamp counter which is indicated
by CU_PTSC MSR_C0010280[PTSC]
* PwrCPUave: CPU average power
i. Determine the ratio of Tsample to Tref by executing CPUID Fn8000_0007.
N = value of CPUID Fn8000_0007_ECX[CpuPwrSampleTimeRatio[15:0]].
ii. Read the full range of the cumulative energy value from the new
MSR MaxCpuSwPwrAcc.
Jmax = value returned.
iii. At time x, software reads CpuSwPwrAcc and samples the PTSC.
Jx = value read from CpuSwPwrAcc and Tx = value read from PTSC.
iv. At time y, software reads CpuSwPwrAcc and samples the PTSC.
Jy = value read from CpuSwPwrAcc and Ty = value read from PTSC.
v. Calculate the average power consumption for a compute unit over
time period (y-x). Unit of result is uWatt:
if (Jy < Jx) // Rollover has occurred
Jdelta = (Jy + Jmax) - Jx
else
Jdelta = Jy - Jx
PwrCPUave = N * Jdelta * 1000 / (Ty - Tx)
Simple example:
root@hr-zp:/home/ray/tip# ./tools/perf/perf stat -a -e 'power/power-pkg/' make -j4
CHK include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
CHK include/generated/timeconst.h
CHK include/generated/bounds.h
CHK include/generated/asm-offsets.h
CALL scripts/checksyscalls.sh
CHK include/generated/compile.h
SKIPPED include/generated/compile.h
Building modules, stage 2.
Kernel: arch/x86/boot/bzImage is ready (#40)
MODPOST 4225 modules
Performance counter stats for 'system wide':
183.44 mWatts power/power-pkg/
341.837270111 seconds time elapsed
root@hr-zp:/home/ray/tip# ./tools/perf/perf stat -a -e 'power/power-pkg/' sleep 10
Performance counter stats for 'system wide':
0.18 mWatts power/power-pkg/
10.012551815 seconds time elapsed
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Ingo Molnar <mingo@kernel.org>
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: jacob.w.shin@gmail.com
Link: http://lkml.kernel.org/r/1457502306-2559-1-git-send-email-ray.huang@amd.com
[ Fixed the modular build. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently CQM (cache quality of service monitoring) is grouping all
events belonging to same PID to use one RMID. However its not counting
all of these different events. Hence we end up with a count of zero
for all events other than the group leader.
The patch tries to address the issue by keeping a flag in the
perf_event.hw which has other CQM related fields. The field is updated
at event creation and during grouping.
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
[peterz: Changed hw_perf_event::is_group_event to an int]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: fenghua.yu@intel.com
Cc: h.peter.anvin@intel.com
Cc: ravi.v.shankar@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1457652732-4499-2-git-send-email-vikas.shivappa@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull networking updates from David Miller:
"Highlights:
1) Support more Realtek wireless chips, from Jes Sorenson.
2) New BPF types for per-cpu hash and arrap maps, from Alexei
Starovoitov.
3) Make several TCP sysctls per-namespace, from Nikolay Borisov.
4) Allow the use of SO_REUSEPORT in order to do per-thread processing
of incoming TCP/UDP connections. The muxing can be done using a
BPF program which hashes the incoming packet. From Craig Gallek.
5) Add a multiplexer for TCP streams, to provide a messaged based
interface. BPF programs can be used to determine the message
boundaries. From Tom Herbert.
6) Add 802.1AE MACSEC support, from Sabrina Dubroca.
7) Avoid factorial complexity when taking down an inetdev interface
with lots of configured addresses. We were doing things like
traversing the entire address less for each address removed, and
flushing the entire netfilter conntrack table for every address as
well.
8) Add and use SKB bulk free infrastructure, from Jesper Brouer.
9) Allow offloading u32 classifiers to hardware, and implement for
ixgbe, from John Fastabend.
10) Allow configuring IRQ coalescing parameters on a per-queue basis,
from Kan Liang.
11) Extend ethtool so that larger link mode masks can be supported.
From David Decotigny.
12) Introduce devlink, which can be used to configure port link types
(ethernet vs Infiniband, etc.), port splitting, and switch device
level attributes as a whole. From Jiri Pirko.
13) Hardware offload support for flower classifiers, from Amir Vadai.
14) Add "Local Checksum Offload". Basically, for a tunneled packet
the checksum of the outer header is 'constant' (because with the
checksum field filled into the inner protocol header, the payload
of the outer frame checksums to 'zero'), and we can take advantage
of that in various ways. From Edward Cree"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1548 commits)
bonding: fix bond_get_stats()
net: bcmgenet: fix dma api length mismatch
net/mlx4_core: Fix backward compatibility on VFs
phy: mdio-thunder: Fix some Kconfig typos
lan78xx: add ndo_get_stats64
lan78xx: handle statistics counter rollover
RDS: TCP: Remove unused constant
RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket
net: smc911x: convert pxa dma to dmaengine
team: remove duplicate set of flag IFF_MULTICAST
bonding: remove duplicate set of flag IFF_MULTICAST
net: fix a comment typo
ethernet: micrel: fix some error codes
ip_tunnels, bpf: define IP_TUNNEL_OPTS_MAX and use it
bpf, dst: add and use dst_tclassid helper
bpf: make skb->tc_classid also readable
net: mvneta: bm: clarify dependencies
cls_bpf: reset class and reuse major in da
ldmvsw: Checkpatch sunvnet.c and sunvnet_common.c
ldmvsw: Add ldmvsw.c driver code
...
Pull NOHZ updates from Ingo Molnar:
"NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors
the NOHZ 'can the tick be stopped?' infrastructure and related code to
be data driven, and harmonizes the naming and handling of all the
various properties"
[ This makes the ugly "fetch_or()" macro that the scheduler used
internally a new generic helper, and does a bad job at it.
I'm pulling it, but I've asked Ingo and Frederic to get this
fixed up ]
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched-clock: Migrate to use new tick dependency mask model
posix-cpu-timers: Migrate to use new tick dependency mask model
sched: Migrate sched to use new tick dependency mask model
sched: Account rr tasks
perf: Migrate perf to use new tick dependency mask model
nohz: Use enum code for tick stop failure tracing message
nohz: New tick dependency mask
nohz: Implement wide kick on top of irq work
atomic: Export fetch_or()
Several cases of overlapping changes, as well as one instance
(vxlan) of a bug fix in 'net' overlapping with code movement
in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull nohz enhancements from Frederic Weisbecker:
"Currently in nohz full configs, the tick dependency is checked
asynchronously by nohz code from interrupt and context switch for each
concerned subsystem with a set of function provided by these. Such
functions are made of many conditions and details that can be heavyweight
as they are called on fastpath: sched_can_stop_tick(),
posix_cpu_timer_can_stop_tick(), perf_event_can_stop_tick()...
Thomas suggested a few months ago to make that tick dependency check
synchronous. Instead of checking subsystems details from each interrupt
to guess if the tick can be stopped, every subsystem that may have a tick
dependency should set itself a flag specifying the state of that
dependency. This way we can verify if we can stop the tick with a single
lightweight mask check on fast path.
This conversion from a pull to a push model to implement tick dependency
is the core feature of this patchset that is split into:
* Nohz wide kick simplification
* Improve nohz tracing
* Introduce tick dependency mask
* Migrate scheduler, posix timers, perf events and sched clock tick
dependencies to the tick dependency mask."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Instead of providing asynchronous checks for the nohz subsystem to verify
perf event tick dependency, migrate perf to the new mask.
Perf needs the tick for two situations:
1) Freq events. We could set the tick dependency when those are
installed on a CPU context. But setting a global dependency on top of
the global freq events accounting is much easier. If people want that
to be optimized, we can still refine that on the per-CPU tick dependency
level. This patch dooesn't change the current behaviour anyway.
2) Throttled events: this is a per-cpu dependency.
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
For PMUs which are not per CPU, but e.g. per package/socket, we want to be
able to store a reference to the underlying per package/socket facility in the
event at init time so we can avoid magic storage constructs in the PMU driver.
This allows us to get rid of the per CPU dance in the intel uncore and RAPL
drivers and avoids a lookup of the per package data in the perf hotpath.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Harish Chegondi <harish.chegondi@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20160222221011.364140369@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_install_in_context() relies upon the context switch hooks to have
scheduled in events when the IPI misses its target -- after all, if
the task has moved from the CPU (or wasn't running at all), it will
have to context switch to run elsewhere.
This however doesn't appear to be happening.
It is possible for the IPI to not happen (task wasn't running) only to
later observe the task running with an inactive context.
The only possible explanation is that the context switch hooks are not
called. Therefore put in a sync_sched() after toggling the jump_label
to guarantee all CPUs will have them enabled before we install an
event.
A simple if (0->1) sync_sched() will not in fact work, because any
further increment can race and complete before the sync_sched().
Therefore we must jump through some hoops.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160224174947.980211985@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Alexander reported that when the 'original' context gets destroyed, no
new clones happen.
This can happen irrespective of the ctx switch optimization, any task
can die, even the parent, and we want to continue monitoring the task
hierarchy until we either close the event or no tasks are left in the
hierarchy.
perf_event_init_context() will attempt to pin the 'parent' context
during clone(). At that point current is the parent, and since current
cannot have exited while executing clone(), its context cannot have
passed through perf_event_exit_task_context(). Therefore
perf_pin_task_context() cannot observe ctx->task == TASK_TOMBSTONE.
However, since inherit_event() does:
if (parent_event->parent)
parent_event = parent_event->parent;
it looks at the 'original' event when it does: is_orphaned_event().
This can return true if the context that contains the this event has
passed through perf_event_exit_task_context(). And thus we'll fail to
clone the perf context.
Fix this by adding a new state: STATE_DEAD, which is set by
perf_release() to indicate that the filedesc (or kernel reference) is
dead and there are no observers for our data left.
Only for STATE_DEAD will is_orphaned_event() be true and inhibit
cloning.
STATE_EXIT is otherwise preserved such that is_event_hup() remains
functional and will report when the observed task hierarchy becomes
empty.
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: eranian@google.com
Cc: oleg@redhat.com
Cc: panand@redhat.com
Cc: sasha.levin@oracle.com
Cc: vince@deater.net
Fixes: c6e5b73242 ("perf: Synchronously clean up child events")
Link: http://lkml.kernel.org/r/20160224174947.919845295@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
. avoid walking the stack when there is no room left in the buffer
. generalize get_perf_callchain() to be called from bpf helper
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The orphan cleanup workqueue doesn't always catch orphans, for example,
if they never schedule after they are orphaned. IOW, the event leak is
still very real. It also wouldn't work for kernel counters.
Doing it synchonously is a little hairy due to lock inversion issues,
but is made to work.
Patch based on work by Alexander Shishkin.
Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is one common bug left in all the event_function_call() users,
between loading ctx->task and getting to the remote_function(),
ctx->task can already have been changed.
Therefore we need to double check and retry if ctx->task != current.
Insert another trampoline specific to event_function_call() that
checks for this and further validates state. This also allows getting
rid of the active/inactive functions.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch reinforces the lockdep checks performed by
perf_cgroup_from_tsk() by passing the perf_event_context
whenever possible. It is okay to not hold the RCU read lock
when we know we hold the ctx->lock. This patch makes sure this
property holds.
In some functions, such as perf_cgroup_sched_in(), we do not
pass the context because we are sure we are holding the RCU
read lock.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: edumazet@google.com
Link: http://lkml.kernel.org/r/1447322404-10920-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We currently use PERF_EVENT_TXN flag to determine if we are in the middle
of a transaction. If in a transaction, we defer the schedulability checks
from pmu->add() operation to the pmu->commit() operation.
Now that we have "transaction types" (PERF_PMU_TXN_ADD, PERF_PMU_TXN_READ)
we can use the type to determine if we are in a transaction and drop the
PERF_EVENT_TXN flag.
When PERF_EVENT_TXN is dropped, the cpuhw->group_flag on some architectures
becomes unused, so drop that field as well.
This is an extension of the Powerpc patch from Peter Zijlstra to s390,
Sparc and x86 architectures.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-11-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Define a new PERF_PMU_TXN_READ interface to read a group of counters
at once.
pmu->start_txn() // Initialize before first event
for each event in group
pmu->read(event); // Queue each event to be read
rc = pmu->commit_txn() // Read/update all queued counters
Note that we use this interface with all PMUs. PMUs that implement this
interface use the ->read() operation to _queue_ the counters to be read
and use ->commit_txn() to actually read all the queued counters at once.
PMUs that don't implement PERF_PMU_TXN_READ ignore ->start_txn() and
->commit_txn() and continue to read counters one at a time.
Thanks to input from Peter Zijlstra.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-9-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, the PMU interface allows reading only one counter at a time.
But some PMUs like the 24x7 counters in Power, support reading several
counters at once. To leveage this functionality, extend the transaction
interface to support a "transaction type".
The first type, PERF_PMU_TXN_ADD, refers to the existing transactions,
i.e. used to _schedule_ all the events on the PMU as a group. A second
transaction type, PERF_PMU_TXN_READ, will be used in a follow-on patch,
by the 24x7 counters to read several counters at once.
Extend the transaction interfaces to the PMU to accept a 'txn_flags'
parameter and use this parameter to ignore any transactions that are
not of type PERF_PMU_TXN_ADD.
Thanks to Peter Zijlstra for his input.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
[peterz: s390 compile fix]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1441336073-22750-3-git-send-email-sukadev@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch add three core perf APIs:
- perf_event_attrs(): export the struct perf_event_attr from struct
perf_event;
- perf_event_get(): get the struct perf_event from the given fd;
- perf_event_read_local(): read the events counters active on the
current CPU;
These APIs are needed when accessing events counters in eBPF programs.
The API perf_event_read_local() comes from Peter and I add the
corresponding SOB.
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
"monitonic raw". Also some enhancements to make the ring buffer even
faster. But the biggest and most noticeable change is the renaming of
the ftrace* files, structures and variables that have to deal with
trace events.
Over the years I've had several developers tell me about their confusion
with what ftrace is compared to events. Technically, "ftrace" is the
infrastructure to do the function hooks, which include tracing and also
helps with live kernel patching. But the trace events are a separate
entity altogether, and the files that affect the trace events should
not be named "ftrace". These include:
include/trace/ftrace.h -> include/trace/trace_events.h
include/linux/ftrace_event.h -> include/linux/trace_events.h
Also, functions that are specific for trace events have also been renamed:
ftrace_print_*() -> trace_print_*()
(un)register_ftrace_event() -> (un)register_trace_event()
ftrace_event_name() -> trace_event_name()
ftrace_trigger_soft_disabled()-> trace_trigger_soft_disabled()
ftrace_define_fields_##call() -> trace_define_fields_##call()
ftrace_get_offsets_##call() -> trace_get_offsets_##call()
Structures have been renamed:
ftrace_event_file -> trace_event_file
ftrace_event_{call,class} -> trace_event_{call,class}
ftrace_event_buffer -> trace_event_buffer
ftrace_subsystem_dir -> trace_subsystem_dir
ftrace_event_raw_##call -> trace_event_raw_##call
ftrace_event_data_offset_##call-> trace_event_data_offset_##call
ftrace_event_type_funcs_##call -> trace_event_type_funcs_##call
And a few various variables and flags have also been updated.
This has been sitting in linux-next for some time, and I have not heard
a single complaint about this rename breaking anything. Mostly because
these functions, variables and structures are mostly internal to the
tracing system and are seldom (if ever) used by anything external to that.
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Merge tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This patch series contains several clean ups and even a new trace
clock "monitonic raw". Also some enhancements to make the ring buffer
even faster. But the biggest and most noticeable change is the
renaming of the ftrace* files, structures and variables that have to
deal with trace events.
Over the years I've had several developers tell me about their
confusion with what ftrace is compared to events. Technically,
"ftrace" is the infrastructure to do the function hooks, which include
tracing and also helps with live kernel patching. But the trace
events are a separate entity altogether, and the files that affect the
trace events should not be named "ftrace". These include:
include/trace/ftrace.h -> include/trace/trace_events.h
include/linux/ftrace_event.h -> include/linux/trace_events.h
Also, functions that are specific for trace events have also been renamed:
ftrace_print_*() -> trace_print_*()
(un)register_ftrace_event() -> (un)register_trace_event()
ftrace_event_name() -> trace_event_name()
ftrace_trigger_soft_disabled() -> trace_trigger_soft_disabled()
ftrace_define_fields_##call() -> trace_define_fields_##call()
ftrace_get_offsets_##call() -> trace_get_offsets_##call()
Structures have been renamed:
ftrace_event_file -> trace_event_file
ftrace_event_{call,class} -> trace_event_{call,class}
ftrace_event_buffer -> trace_event_buffer
ftrace_subsystem_dir -> trace_subsystem_dir
ftrace_event_raw_##call -> trace_event_raw_##call
ftrace_event_data_offset_##call-> trace_event_data_offset_##call
ftrace_event_type_funcs_##call -> trace_event_type_funcs_##call
And a few various variables and flags have also been updated.
This has been sitting in linux-next for some time, and I have not
heard a single complaint about this rename breaking anything. Mostly
because these functions, variables and structures are mostly internal
to the tracing system and are seldom (if ever) used by anything
external to that"
* tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
ring_buffer: Allow to exit the ring buffer benchmark immediately
ring-buffer-benchmark: Fix the wrong type
ring-buffer-benchmark: Fix the wrong param in module_param
ring-buffer: Add enum names for the context levels
ring-buffer: Remove useless unused tracing_off_permanent()
ring-buffer: Give NMIs a chance to lock the reader_lock
ring-buffer: Add trace_recursive checks to ring_buffer_write()
ring-buffer: Allways do the trace_recursive checks
ring-buffer: Move recursive check to per_cpu descriptor
ring-buffer: Add unlikelys to make fast path the default
tracing: Rename ftrace_get_offsets_##call() to trace_event_get_offsets_##call()
tracing: Rename ftrace_define_fields_##call() to trace_event_define_fields_##call()
tracing: Rename ftrace_event_type_funcs_##call to trace_event_type_funcs_##call
tracing: Rename ftrace_data_offset_##call to trace_event_data_offset_##call
tracing: Rename ftrace_raw_##call event structures to trace_event_raw_##call
tracing: Rename ftrace_trigger_soft_disabled() to trace_trigger_soft_disabled()
tracing: Rename FTRACE_EVENT_FL_* flags to EVENT_FILE_FL_*
tracing: Rename struct ftrace_subsystem_dir to trace_subsystem_dir
tracing: Rename ftrace_event_name() to trace_event_name()
tracing: Rename FTRACE_MAX_EVENT to TRACE_EVENT_TYPE_MAX
...
Pull ARM updates from Russell King:
"Bigger items included in this update are:
- A series of updates from Arnd for ARM randconfig build failures
- Updates from Dmitry for StrongARM SA-1100 to move IRQ handling to
drivers/irqchip/
- Move ARMs SP804 timer to drivers/clocksource/
- Perf updates from Mark Rutland in preparation to move the ARM perf
code into drivers/ so it can be shared with ARM64.
- MCPM updates from Nicolas
- Add support for taking platform serial number from DT
- Re-implement Keystone2 physical address space switch to conform to
architecture requirements
- Clean up ARMv7 LPAE code, which goes in hand with the Keystone2
changes.
- L2C cleanups to avoid unlocking caches if we're prevented by the
secure support to unlock.
- Avoid cleaning a potentially dirty cache containing stale data on
CPU initialisation
- Add ARM-only entry point for secondary startup (for machines that
can only call into a Thumb kernel in ARM mode). Same thing is also
done for the resume entry point.
- Provide arch_irqs_disabled via asm-generic
- Enlarge ARMv7M vector table
- Always use BFD linker for VDSO, as gold doesn't accept some of the
options we need.
- Fix an incorrect BSYM (for Thumb symbols) usage, and convert all
BSYM compiler macros to a "badr" (for branch address).
- Shut up compiler warnings provoked by our cmpxchg() implementation.
- Ensure bad xchg sizes fail to link"
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (75 commits)
ARM: Fix build if CLKDEV_LOOKUP is not configured
ARM: fix new BSYM() usage introduced via for-arm-soc branch
ARM: 8383/1: nommu: avoid deprecated source register on mov
ARM: 8391/1: l2c: add options to overwrite prefetching behavior
ARM: 8390/1: irqflags: Get arch_irqs_disabled from asm-generic
ARM: 8387/1: arm/mm/dma-mapping.c: Add arm_coherent_dma_mmap
ARM: 8388/1: tcm: Don't crash when TCM banks are protected by TrustZone
ARM: 8384/1: VDSO: force use of BFD linker
ARM: 8385/1: VDSO: group link options
ARM: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
ARM: remove __bad_xchg definition
ARM: 8369/1: ARMv7M: define size of vector table for Vybrid
ARM: 8382/1: clocksource: make ARM_TIMER_SP804 depend on GENERIC_SCHED_CLOCK
ARM: 8366/1: move Dual-Timer SP804 driver to drivers/clocksource
ARM: 8365/1: introduce sp804_timer_disable and remove arm_timer.h inclusion
ARM: 8364/1: fix BE32 module loading
ARM: 8360/1: add secondary_startup_arm prototype in header file
ARM: 8359/1: correct secondary_startup_arm mode
ARM: proc-v7: sanitise and document registers around errata
ARM: proc-v7: clean up MIDR access
...
Pull timer updates from Thomas Gleixner:
"A rather largish update for everything time and timer related:
- Cache footprint optimizations for both hrtimers and timer wheel
- Lower the NOHZ impact on systems which have NOHZ or timer migration
disabled at runtime.
- Optimize run time overhead of hrtimer interrupt by making the clock
offset updates smarter
- hrtimer cleanups and removal of restrictions to tackle some
problems in sched/perf
- Some more leap second tweaks
- Another round of changes addressing the 2038 problem
- First step to change the internals of clock event devices by
introducing the necessary infrastructure
- Allow constant folding for usecs/msecs_to_jiffies()
- The usual pile of clockevent/clocksource driver updates
The hrtimer changes contain updates to sched, perf and x86 as they
depend on them plus changes all over the tree to cleanup API changes
and redundant code, which got copied all over the place. The y2038
changes touch s390 to remove the last non 2038 safe code related to
boot/persistant clock"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
clocksource: Increase dependencies of timer-stm32 to limit build wreckage
timer: Minimize nohz off overhead
timer: Reduce timer migration overhead if disabled
timer: Stats: Simplify the flags handling
timer: Replace timer base by a cpu index
timer: Use hlist for the timer wheel hash buckets
timer: Remove FIFO "guarantee"
timers: Sanitize catchup_timer_jiffies() usage
hrtimer: Allow hrtimer::function() to free the timer
seqcount: Introduce raw_write_seqcount_barrier()
seqcount: Rename write_seqcount_barrier()
hrtimer: Fix hrtimer_is_queued() hole
hrtimer: Remove HRTIMER_STATE_MIGRATE
selftest: Timers: Avoid signal deadlock in leap-a-day
timekeeping: Copy the shadow-timekeeper over the real timekeeper last
clockevents: Check state instead of mode in suspend/resume path
selftests: timers: Add leap-second timer edge testing to leap-a-day.c
ntp: Do leapsecond adjustment in adjtimex read path
time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge
ntp: Introduce and use SECS_PER_DAY macro instead of 86400
...
After enlarging the PEBS interrupt threshold, there may be some mixed up
PEBS samples which are discarded by the kernel.
This patch makes the kernel emit a PERF_RECORD_LOST_SAMPLES record with
the number of possible discarded records when it is impossible to demux
the samples.
It makes sure the user is not left in the dark about such discards.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1431285195-14269-8-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When the PEBS interrupt threshold is larger than one record and the
machine supports multiple PEBS events, the records of these events are
mixed up and we need to demultiplex them.
Demuxing the records is hard because the hardware is deficient. The
hardware has two issues that, when combined, create impossible
scenarios to demux.
The first issue is that the 'status' field of the PEBS record is a copy
of the GLOBAL_STATUS MSR at PEBS assist time. To see why this is a
problem let us first describe the regular PEBS cycle:
A) the CTRn value reaches 0:
- the corresponding bit in GLOBAL_STATUS gets set
- we start arming the hardware assist
< some unspecified amount of time later -- this could cover multiple
events of interest >
B) the hardware assist is armed, any next event will trigger it
C) a matching event happens:
- the hardware assist triggers and generates a PEBS record
this includes a copy of GLOBAL_STATUS at this moment
- if we auto-reload we (re)set CTRn
- we clear the relevant bit in GLOBAL_STATUS
Now consider the following chain of events:
A0, B0, A1, C0
The event generated for counter 0 will include a status with counter 1
set, even though its not at all related to the record. A similar thing
can happen with a !PEBS event if it just happens to overflow at the
right moment.
The second issue is that the hardware will only emit one record for two
or more counters if the event that triggers the assist is 'close'. The
'close' can be several cycles. In some cases even the complete assist,
if the event is something that doesn't need retirement.
For instance, consider this chain of events:
A0, B0, A1, B1, C01
Where C01 is an event that triggers both hardware assists, we will
generate but a single record, but again with both counters listed in the
status field.
This time the record pertains to both events.
Note that these two cases are different but undistinguishable with the
data as generated. Therefore demuxing records with multiple PEBS bits
(we can safely ignore status bits for !PEBS counters) is impossible.
Furthermore we cannot emit the record to both events because that might
cause a data leak -- the events might not have the same privileges -- so
what this patch does is discard such events.
The assumption/hope is that such discards will be rare.
Here lists some possible ways you may get high discard rate.
- when you count the same thing multiple times. But it is not a useful
configuration.
- you can be unfortunate if you measure with a userspace only PEBS
event along with either a kernel or unrestricted PEBS event. Imagine
the event triggering and setting the overflow flag right before
entering the kernel. Then all kernel side events will end up with
multiple bits set.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
[ Changelog improvements. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1430940834-8964-4-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In certain circumstances it may not be possible to schedule particular
events due to constraints other than a lack of hardware counters (e.g.
on big.LITTLE systems where CPUs support different events). The core
perf event code does not distinguish these cases and pessimistically
assumes that any failure to schedule an event means that it is not worth
attempting to schedule later events, even if some hardware counters are
still unused.
When an event a pmu cannot schedule exists in a flexible group list it
can unnecessarily prevent event groups following it in the list from
being scheduled (until it is rotated to the end of the list). This means
some events are scheduled for only a portion of the time they could be,
and for short running programs no events may be scheduled if the list is
initially sorted in an unfortunate order.
This patch adds a new (optional) filter_match function pointer to struct
pmu which a pmu driver can use to tell perf core when an event matches
pmu-specific scheduling requirements. This plugs into the existing
event_filter_match logic, and makes it possible to avoid the scheduling
problem described above. When no filter is provided by the PMU, the
existing behaviour is retained.
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
'int' is really not a proper data type for an MSR. Use u32 to make it
clear that we are dealing with a 32-bit unsigned hardware value.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Matt Fleming <matt.fleming@intel.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: Will Auld <will.auld@intel.com>
Link: http://lkml.kernel.org/r/20150518235149.919350144@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 43b4578071 ("perf/x86: Reduce stack usage of
x86_schedule_events()") violated the rule that 'fake' scheduling; as
used for event/group validation; should not change the event state.
This went mostly un-noticed because repeated calls of
x86_pmu::get_event_constraints() would give the same result. And
x86_pmu::put_event_constraints() would mostly not do anything.
Commit e979121b1b ("perf/x86/intel: Implement cross-HT corruption
bug workaround") made the situation much worse by actually setting the
event->hw.constraint value to NULL, so when validation and actual
scheduling interact we get NULL ptr derefs.
Fix it by removing the constraint pointer from the event and move it
back to an array, this time in cpuc instead of on the stack.
validate_group()
x86_schedule_events()
event->hw.constraint = c; # store
<context switch>
perf_task_event_sched_in()
...
x86_schedule_events();
event->hw.constraint = c2; # store
...
put_event_constraints(event); # assume failure to schedule
intel_put_event_constraints()
event->hw.constraint = NULL;
<context switch end>
c = event->hw.constraint; # read -> NULL
if (!test_bit(hwc->idx, c->idxmsk)) # <- *BOOM* NULL deref
This in particular is possible when the event in question is a
cpu-wide event and group-leader, where the validate_group() tries to
add an event to the group.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Hunter <ahh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 43b4578071 ("perf/x86: Reduce stack usage of x86_schedule_events()")
Fixes: e979121b1b ("perf/x86/intel: Implement cross-HT corruption bug workaround")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the below two commits (see Fixes) we have periodic timers that can
stop themselves when they're no longer required, but need to be
(re)-started when their idle condition changes.
Further complications is that we want the timer handler to always do
the forward such that it will always correctly deal with the overruns,
and we do not want to race such that the handler has already decided
to stop, but the (external) restart sees the timer still active and we
end up with a 'lost' timer.
The problem with the current code is that the re-start can come before
the callback does the forward, at which point the forward from the
callback will WARN about forwarding an enqueued timer.
Now, conceptually its easy to detect if you're before or after the fwd
by comparing the expiration time against the current time. Of course,
that's expensive (and racy) because we don't have the current time.
Alternatively one could cache this state inside the timer, but then
everybody pays the overhead of maintaining this extra state, and that
is undesired.
The only other option that I could see is the external timer_active
variable, which I tried to kill before. I would love a nicer interface
for this seemingly simple 'problem' but alas.
Fixes: 272325c482 ("perf: Fix mux_interval hrtimer wreckage")
Fixes: 77a4d1a1b9 ("sched: Cleanup bandwidth timers")
Cc: pjt@google.com
Cc: tglx@linutronix.de
Cc: klamm@yandex-team.ru
Cc: mingo@kernel.org
Cc: bsegall@google.com
Cc: hpa@zytor.com
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150514102311.GX21418@twins.programming.kicks-ass.net
The name "ftrace" really refers to the function hook infrastructure. It
is not about the trace_events. The structures ftrace_event_call and
ftrace_event_class have nothing to do with the function hooks, and are
really trace_event structures. Rename ftrace_event_* to trace_event_*.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Stephane asked about PERF_COUNT_SW_CPU_MIGRATIONS and I realized it
was borken:
> The problem is that the task isn't actually scheduled while its being
> migrated (obviously), and if its not scheduled, the counters aren't
> scheduled either, so there's no observing of the fact.
>
> A further problem with migrations is that many migrations happen from
> softirq context, which is nested inside the 'random' task context of
> whoemever happens to run at that time, similarly for the wakeup
> migrations triggered from (soft)irq context. All those end up being
> accounted in the task that's currently running, eg. your 'ls'.
The below cures this by marking a task as migrated and accounting it
on the subsequent sched_in().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For counters that generate AUX data that is bound to the context of a
running task, such as instruction tracing, the decoder needs to know
exactly which task is running when the event is first scheduled in,
before the first sched_switch. The decoder's need to know this stems
from the fact that instruction flow trace decoding will almost always
require program's object code in order to reconstruct said flow and
for that we need at least its pid/tid in the perf stream.
To single out such instruction tracing pmus, this patch introduces
ITRACE PMU capability. The reason this is not part of RECORD_AUX
record is that not all pmus capable of generating AUX data need this,
and the opposite is *probably* also true.
While sched_switch covers for most cases, there are two problems with it:
the consumer will need to process events out of order (that is, having
found RECORD_AUX, it will have to skip forward to the nearest sched_switch
to figure out which task it was, then go back to the actual trace to
decode it) and it completely misses the case when the tracing is enabled
and disabled before sched_switch, for example, via PERF_EVENT_IOC_DISABLE.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-15-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For pmus that wish to write data to ring buffer's AUX area, provide
perf_aux_output_{begin,end}() calls to initiate/commit data writes,
similarly to perf_output_{begin,end}. These also use the same output
handle structure. Also, similarly to software counterparts, these
will direct inherited events' output to parents' ring buffers.
After the perf_aux_output_begin() returns successfully, handle->size
is set to the maximum amount of data that can be written wrt aux_tail
pointer, so that no data that the user hasn't seen will be overwritten,
therefore this should always be called before hardware writing is
enabled. On success, this will return the pointer to pmu driver's
private structure allocated for this aux area by pmu::setup_aux. Same
pointer can also be retrieved using perf_get_aux() while hardware
writing is enabled.
PMU driver should pass the actual amount of data written as a parameter
to perf_aux_output_end(). All hardware writes should be completed and
visible before this one is called.
Additionally, perf_aux_output_skip() will adjust output handle and
aux_head in case some part of the buffer has to be skipped over to
maintain hardware's alignment constraints.
Nested writers are forbidden and guards are in place to catch such
attempts.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-8-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Usually, pmus that do, for example, instruction tracing, would only ever
be able to have one event per task per cpu (or per perf_event_context). For
such pmus it makes sense to disallow creating conflicting events early on,
so as to provide consistent behavior for the user.
This patch adds a pmu capability that indicates such constraint on event
creation.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1422613866-113186-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For pmus that don't support scatter-gather for AUX data in hardware, it
might still make sense to implement software double buffering to avoid
losing data while the user is reading data out. For this purpose, add
a pmu capability that guarantees multiple high-order chunks for AUX buffer,
so that the pmu driver can do switchover tricks.
To make use of this feature, add PERF_PMU_CAP_AUX_SW_DOUBLEBUF to your
pmu's capability mask. This will make the ring buffer AUX allocation code
ensure that the biggest high order allocation for the aux buffer pages is
no bigger than half of the total requested buffer size, thus making sure
that the buffer has at least two high order allocations.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-5-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some pmus (such as BTS or Intel PT without multiple-entry ToPA capability)
don't support scatter-gather and will prefer larger contiguous areas for
their output regions.
This patch adds a new pmu capability to request higher order allocations.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-4-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch introduces "AUX space" in the perf mmap buffer, intended for
exporting high bandwidth data streams to userspace, such as instruction
flow traces.
AUX space is a ring buffer, defined by aux_{offset,size} fields in the
user_page structure, and read/write pointers aux_{head,tail}, which abide
by the same rules as data_* counterparts of the main perf buffer.
In order to allocate/mmap AUX, userspace needs to set up aux_offset to
such an offset that will be greater than data_offset+data_size and
aux_size to be the desired buffer size. Both need to be page aligned.
Then, same aux_offset and aux_size should be passed to mmap() call and
if everything adds up, you should have an AUX buffer as a result.
Pages that are mapped into this buffer also come out of user's mlock
rlimit plus perf_event_mlock_kb allowance.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-3-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While thinking on the whole clock discussion it occurred to me we have
two distinct uses of time:
1) the tracking of event/ctx/cgroup enabled/running/stopped times
which includes the self-monitoring support in struct
perf_event_mmap_page.
2) the actual timestamps visible in the data records.
And we've been conflating them.
The first is all about tracking time deltas, nobody should really care
in what time base that happens, its all relative information, as long
as its internally consistent it works.
The second however is what people are worried about when having to
merge their data with external sources. And here we have the
discussion on MONOTONIC vs MONOTONIC_RAW etc..
Where MONOTONIC is good for correlating between machines (static
offset), MONOTNIC_RAW is required for correlating against a fixed rate
hardware clock.
This means configurability; now 1) makes that hard because it needs to
be internally consistent across groups of unrelated events; which is
why we had to have a global perf_clock().
However, for 2) it doesn't really matter, perf itself doesn't care
what it writes into the buffer.
The below patch makes the distinction between these two cases by
adding perf_event_clock() which is used for the second case. It
further makes this configurable on a per-event basis, but adds a few
sanity checks such that we cannot combine events with different clocks
in confusing ways.
And since we then have per-event configurability we might as well
retain the 'legacy' behaviour as a default.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add support for task events as well as system-wide events. This change
has a big impact on the way that we gather LLC occupancy values in
intel_cqm_event_read().
Currently, for system-wide (per-cpu) events we defer processing to
userspace which knows how to discard all but one cpu result per package.
Things aren't so simple for task events because we need to do the value
aggregation ourselves. To do this, we defer updating the LLC occupancy
value in event->count from intel_cqm_event_read() and do an SMP
cross-call to read values for all packages in intel_cqm_event_count().
We need to ensure that we only do this for one task event per cache
group, otherwise we'll report duplicate values.
If we're a system-wide event we want to fallback to the default
perf_event_count() implementation. Refactor this into a common function
so that we don't duplicate the code.
Also, introduce PERF_TYPE_INTEL_CQM, since we need a way to track an
event's task (if the event isn't per-cpu) inside of the Intel CQM PMU
driver. This task information is only availble in the upper layers of
the perf infrastructure.
Other perf backends stash the target task in event->hw.*target so we
need to do something similar. The task is used to determine whether
events should share a cache group and an RMID.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/1422038748-21397-8-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Future Intel Xeon processors support a Cache QoS Monitoring feature that
allows tracking of the LLC occupancy for a task or task group, i.e. the
amount of data in pulled into the LLC for the task (group).
Currently the PMU only supports per-cpu events. We create an event for
each cpu and read out all the LLC occupancy values.
Because this results in duplicate values being written out to userspace,
we also export a .per-pkg event file so that the perf tools only
accumulate values for one cpu per package.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/1422038748-21397-6-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For PMU drivers that record per-package counters, the ->count variable
cannot be used to record an accurate aggregated value, since it's not
possible to perform SMP cross-calls to cpus on other packages from the
context in which we update ->count.
Introduce a new optional ->count() accessor function that can be used to
customize how values are collected. If a PMU driver doesn't provide a
->count() function, we fallback to the existing code.
There is necessarily a window of staleness with this approach because
the task that generated the counter value may not have been scheduled by
the cpu recently.
An alternative and more complex approach would be to use a hrtimer to
periodically refresh the values from a more permissive scheduling
context. So, we're trading off complexity for accuracy.
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/1422038748-21397-3-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move perf_cgroup_from_task() from kernel/events/ to include/linux/ along
with the necessary struct definitions, so that it can be used by the PMU
code.
When the upcoming Intel Cache Monitoring PMU driver assigns monitoring
IDs to perf events, it needs to be able to check whether any two
monitoring events overlap (say, a cgroup and task event), which means we
need to be able to lookup the cgroup associated with a task (if any).
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/1422038748-21397-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The recent LBR rework for x86 left a stray flush_branch_stack() user in
the PowerPC code, fix that up.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use event->attr.branch_sample_type to replace
intel_pmu_needs_lbr_smpl() for avoiding duplicated code that
implicitly enables the LBR.
Currently, branch stack can be enabled by user explicitly requesting
branch sampling or implicit branch sampling to correct PEBS skid.
For user explicitly requested branch sampling, the branch_sample_type
is explicitly set by user. For PEBS case, the branch_sample_type is also
implicitly set to PERF_SAMPLE_BRANCH_ANY in x86_pmu_hw_config.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-11-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Introduce a new flag PERF_ATTACH_TASK_DATA for perf event's attach
stata. The flag is set by PMU's event_init() callback, it indicates
that perf event needs PMU specific data.
The PMU specific data are initialized to zeros. Later patches will
use PMU specific data to save LBR stack.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-6-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Previous commit introduces context switch callback, its function
overlaps with the flush branch stack callback. So we can use the
context switch callback to flush LBR stack.
This patch adds code that uses the flush branch callback to
flush the LBR stack when task is being scheduled in. The callback
is enabled only when there are events use the LBR hardware. This
patch also removes all old flush branch stack code.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-4-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The callback is invoked when process is scheduled in or out.
It provides mechanism for later patches to save/store the LBR
stack. For the schedule in case, the callback is invoked at
the same place that flush branch stack callback is invoked.
So it also can replace the flush branch stack callback. To
avoid unnecessary overhead, the callback is enabled only when
there are events use the LBR stack.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/1415156173-10035-3-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 perf updates from Ingo Molnar:
"This series tightens up RDPMC permissions: currently even highly
sandboxed x86 execution environments (such as seccomp) have permission
to execute RDPMC, which may leak various perf events / PMU state such
as timing information and other CPU execution details.
This 'all is allowed' RDPMC mode is still preserved as the
(non-default) /sys/devices/cpu/rdpmc=2 setting. The new default is
that RDPMC access is only allowed if a perf event is mmap-ed (which is
needed to correctly interpret RDPMC counter values in any case).
As a side effect of these changes CR4 handling is cleaned up in the
x86 code and a shadow copy of the CR4 value is added.
The extra CR4 manipulation adds ~ <50ns to the context switch cost
between rdpmc-capable and rdpmc-non-capable mms"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks
perf/x86: Only allow rdpmc if a perf_event is mapped
perf: Pass the event to arch_perf_update_userpage()
perf: Add pmu callbacks to track event mapping and unmapping
x86: Add a comment clarifying LDT context switching
x86: Store a per-cpu shadow copy of CR4
x86: Clean up cr4 manipulation
Including:
- Update of all defconfigs
- Addition of a bunch of config options to modernise our defconfigs
- Some PS3 updates from Geoff
- Optimised memcmp for 64 bit from Anton
- Fix for kprobes that allows 'perf probe' to work from Naveen
- Several cxl updates from Ian & Ryan
- Expanded support for the '24x7' PMU from Cody & Sukadev
- Freescale updates from Scott:
"Highlights include 8xx optimizations, some more work on datapath device
tree content, e300 machine check support, t1040 corenet error reporting,
and various cleanups and fixes."
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Merge tag 'powerpc-3.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux
Pull powerpc updates from Michael Ellerman:
- Update of all defconfigs
- Addition of a bunch of config options to modernise our defconfigs
- Some PS3 updates from Geoff
- Optimised memcmp for 64 bit from Anton
- Fix for kprobes that allows 'perf probe' to work from Naveen
- Several cxl updates from Ian & Ryan
- Expanded support for the '24x7' PMU from Cody & Sukadev
- Freescale updates from Scott:
"Highlights include 8xx optimizations, some more work on datapath
device tree content, e300 machine check support, t1040 corenet
error reporting, and various cleanups and fixes"
* tag 'powerpc-3.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (102 commits)
cxl: Add missing return statement after handling AFU errror
cxl: Fail AFU initialisation if an invalid configuration record is found
cxl: Export optional AFU configuration record in sysfs
powerpc/mm: Warn on flushing tlb page in kernel context
powerpc/powernv: Add OPAL soft-poweroff routine
powerpc/perf/hv-24x7: Document sysfs event description entries
powerpc/perf/hv-gpci: add the remaining gpci requests
powerpc/perf/{hv-gpci, hv-common}: generate requests with counters annotated
powerpc/perf/hv-24x7: parse catalog and populate sysfs with events
perf: define EVENT_DEFINE_RANGE_FORMAT_LITE helper
perf: add PMU_EVENT_ATTR_STRING() helper
perf: provide sysfs_show for struct perf_pmu_events_attr
powerpc/kernel: Avoid initializing device-tree pointer twice
powerpc: Remove old compile time disabled syscall tracing code
powerpc/kernel: Make syscall_exit a local label
cxl: Fix device_node reference counting
powerpc/mm: bail out early when flushing TLB page
powerpc: defconfigs: add MTD_SPI_NOR (new dependency for M25P80)
perf/powerpc: reset event hw state when adding it to the PMU
powerpc/qe: Use strlcpy()
...
Currently the adjusments made as part of perf_event_task_tick() use the
percpu rotation lists to iterate over any active PMU contexts, but these
are not used by the context rotation code, having been replaced by
separate (per-context) hrtimer callbacks. However, some manipulation of
the rotation lists (i.e. removal of contexts) has remained in
perf_rotate_context(). This leads to the following issues:
* Contexts are not always removed from the rotation lists. Removal of
PMUs which have been placed in rotation lists, but have not been
removed by a hrtimer callback can result in corruption of the rotation
lists (when memory backing the context is freed).
This has been observed to result in hangs when PMU drivers built as
modules are inserted and removed around the creation of events for
said PMUs.
* Contexts which do not require rotation may be removed from the
rotation lists as a result of a hrtimer, and will not be considered by
the unthrottling code in perf_event_task_tick.
This patch fixes the issue by updating the rotation ist when events are
scheduled in/out, ensuring that each rotation list stays in sync with
the HW state. As each event holds a refcount on the module of its PMU,
this ensures that when a PMU module is unloaded none of its CPU contexts
can be in a rotation list. By maintaining a list of perf_event_contexts
rather than perf_event_cpu_contexts, we don't need separate paths to
handle the cpu and task contexts, which also makes the code a little
simpler.
As the rotation_list variables are not used for rotation, these are
renamed to active_ctx_list, which better matches their current function.
perf_pmu_rotate_{start,stop} are renamed to
perf_pmu_ctx_{activate,deactivate}.
Reported-by: Johannes Jensen <johannes.jensen@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <Will.Deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150129134511.GR17721@leverpostej
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Helper for constructing static struct perf_pmu_events_attr s.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(struct perf_pmu_events_attr) is defined in include/linux/perf_event.h,
but the only "show" for it is in x86 and contains x86 specific stuff.
Make a generic one for those of us who are just using the event_str.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The fix from 9fc81d8742 ("perf: Fix events installation during
moving group") was incomplete in that it failed to recognise that
creating a group with events for different CPUs is semantically
broken -- they cannot be co-scheduled.
Furthermore, it leads to real breakage where, when we create an event
for CPU Y and then migrate it to form a group on CPU X, the code gets
confused where the counter is programmed -- triggered in practice
as well by me via the perf fuzzer.
Fix this by tightening the rules for creating groups. Only allow
grouping of counters that can be co-scheduled in the same context.
This means for the same task and/or the same cpu.
Fixes: 9fc81d8742 ("perf: Fix events installation during moving group")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.090683288@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both Linus (most recent) and Steve (a while ago) reported that perf
related callbacks have massive stack bloat.
The problem is that software events need a pt_regs in order to
properly report the event location and unwind stack. And because we
could not assume one was present we allocated one on stack and filled
it with minimal bits required for operation.
Now, pt_regs is quite large, so this is undesirable. Furthermore it
turns out that most sites actually have a pt_regs pointer available,
making this even more onerous, as the stack space is pointless waste.
This patch addresses the problem by observing that software events
have well defined nesting semantics, therefore we can use static
per-cpu storage instead of on-stack.
Linus made the further observation that all but the scheduler callers
of perf_sw_event() have a pt_regs available, so we change the regular
perf_sw_event() to require a valid pt_regs (where it used to be
optional) and add perf_sw_event_sched() for the scheduler.
We have a scheduler specific call instead of a more generic _noregs()
like construct because we can assume non-recursion from the scheduler
and thereby simplify the code further (_noregs would have to put the
recursion context call inline in order to assertain which __perf_regs
element to use).
One last note on the implementation of perf_trace_buf_prepare(); we
allow .regs = NULL for those cases where we already have a pt_regs
pointer available and do not need another.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Link: http://lkml.kernel.org/r/20141216115041.GW3337@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On x86_64, at least, task_pt_regs may be only partially initialized
in many contexts, so x86_64 should not use it without extra care
from interrupt context, let alone NMI context.
This will allow x86_64 to override the logic and will supply some
scratch space to use to make a cleaner copy of user regs.
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: chenggang.qcg@taobao.com
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/e431cd4c18c2e1c44c774f10758527fb2d1025c4.1420396372.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch reorders fields in the perf_sample_data struct in order to
minimize the number of cachelines touched in perf_sample_data_init().
It also removes some intializations which are redundant with the code
in kernel/events/core.c
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1411559322-16548-7-git-send-email-eranian@google.com
Cc: cebbert.lkml@gmail.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: jolsa@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Enable capture of interrupted machine state for each sample.
Registers to sample are passed per event in the sample_regs_intr bitmask.
To sample interrupt machine state, the PERF_SAMPLE_INTR_REGS must be passed in
sample_type.
The list of available registers is arch dependent and provided by asm/perf_regs.h
Registers are laid out as u64 in the order of the bit order of sample_intr_regs.
This patch also adds a new ABI version PERF_ATTR_SIZE_VER4 because we extend
the perf_event_attr struct with a new u64 field.
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: cebbert.lkml@gmail.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/1411559322-16548-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Adding new perf event state to indicate that the monitored task has
exited. In this case the event stays alive until the owner task exits
or close the event fd while providing the last data through the read
syscall and ring buffer.
Instead it needs to propagate the error info (monitored task has died)
via poll and read syscalls by returning POLLHUP and 0 respectively.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140811120102.GY9918@twins.programming.kicks-ass.net
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-t5y3w8jjx6tfo5w8y6oajsjq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch fixes issues introuduce by Andi's previous patch 'Revamp PEBS'
series.
This patch fixes the following:
- precise_store_data_hsw() encode the mem op type whenever we can
- precise_store_data_hsw set the default data source correctly
- 0 is not a valid init value for data source. Define PERF_MEM_NA as the
default value
This bug was actually introduced by
commit 722e76e60f
Author: Stephane Eranian <eranian@google.com>
Date: Thu May 15 17:56:44 2014 +0200
fix Haswell precise store data source encoding
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1407785233-32193-4-git-send-email-eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: ak@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In cases when the owner task exits before the workload and the
workload made some forks, all the events stay in until the last
workload process exits. Thats' because each child event holds
parent reference.
We want to release all children events once the parent is gone,
because at that time there's no process to read them anyway, so
they're just eating resources.
This removal races with process exit, which removes all events
and fork, which clone events. To be clear of those two, adding
work queue to remove orphaned child for context in case such
event is detected.
Using delayed work queue (with delay == 1), because we queue this
work under perf scheduler callbacks. Normal work queue tries to wake
up the queue process, which deadlocks on rq->lock in this place.
Also preventing clones from abandoned parent event.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406896382-18404-4-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf tools like 'perf report' can aggregate samples by comm strings,
which generally works. However, there are other potential use-cases.
For example, to pair up 'calls' with 'returns' accurately (from branch
events like Intel BTS) it is necessary to identify whether the process
has exec'd. Although a comm event is generated when an 'exec' happens
it is also generated whenever the comm string is changed on a whim
(e.g. by prctl PR_SET_NAME). This patch adds a flag to the comm event
to differentiate one case from the other.
In order to determine whether the kernel supports the new flag, a
selection bit named 'exec' is added to struct perf_event_attr. The
bit does nothing but will cause perf_event_open() to fail if the bit
is set on kernels that do not have it defined.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/537D9EBE.7030806@intel.com
Cc: Paul Mackerras <paulus@samba.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_event_comm() assumes that set_task_comm() is only called on
exec(), and in particular that its only called on current.
Neither are true, as Dave reported a WARN triggered by set_task_comm()
being called on !current.
Separate the exec() hook from the comm hook.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20140521153219.GH5226@laptop.programming.kicks-ass.net
[ Build fix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add common code to generate -ENOTSUPP at event creation time if an
architecture attempts to create a sampled event and
PERF_PMU_NO_INTERRUPT is set.
This adds a new pmu->capabilities flag. Initially we only support
PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating
hardware interrupts) but there are other capabilities that can be
added later.
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Will Deacon <will.deacon@arm.com>
[peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Alexander noticed that we use RCU iteration on rb->event_list but do
not use list_{add,del}_rcu() to add,remove entries to that list, nor
do we observe proper grace periods when re-using the entries.
Merge ring_buffer_detach() into ring_buffer_attach() such that
attaching to the NULL buffer is detaching.
Furthermore, ensure that between any 'detach' and 'attach' of the same
event we observe the required grace period, but only when strictly
required. In effect this means that only ioctl(.request =
PERF_EVENT_IOC_SET_OUTPUT) will wait for a grace period, while the
normal initial attach and final detach will not be delayed.
This patch should, I think, do the right thing under all
circumstances, the 'normal' cases all should never see the extra grace
period, but the two cases:
1) PERF_EVENT_IOC_SET_OUTPUT on an event which already has a
ring_buffer set, will now observe the required grace period between
removing itself from the old and attaching itself to the new buffer.
This case is 'simple' in that both buffers are present in
perf_event_set_output() one could think an unconditional
synchronize_rcu() would be sufficient; however...
2) an event that has a buffer attached, the buffer is destroyed
(munmap) and then the event is attached to a new/different buffer
using PERF_EVENT_IOC_SET_OUTPUT.
This case is more complex because the buffer destruction does:
ring_buffer_attach(.rb = NULL)
followed by the ioctl() doing:
ring_buffer_attach(.rb = foo);
and we still need to observe the grace period between these two
calls due to us reusing the event->rb_entry list_head.
In order to make 2 happen we use Paul's latest cond_synchronize_rcu()
call.
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507123526.GD13658@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch adds support for building PMU driver as module. It exports
the functions perf_pmu_{register,unregister}() and adds reference tracking
for the PMU driver module.
When the PMU driver is built as a module, each active event of the PMU
holds a reference to the driver module.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1395133004-23205-1-git-send-email-zheng.z.yan@intel.com
Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the perf subsystem's hotplug notifier by using this latter form of
callback registration.
Also provide a bare-bones version of perf_cpu_notifier() that doesn't
invoke the notifiers for the already online CPUs. This would be useful
for subsystems that need to perform a different set of initialization
for the already online CPUs, or don't need the initialization altogether.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch fixes a problem with the initialization of the
struct perf_event active_entry field. It is defined inside
an anonymous union and was initialized in perf_event_alloc()
using INIT_LIST_HEAD(). However at that time, we do not know
whether the event is going to use active_entry or hlist_entry (SW).
Or at last, we don't want to make that determination there.
The problem is that hlist and list_head are not initialized
the same way. One is okay with NULL (from kzmalloc), the other
needs to pointers to point to self.
This patch resolves this problem by dropping the union.
This will avoid problems later on, if someone starts using
active_entry or hlist_entry without verifying that they
actually overlap. This also solves the initialization
problem.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: vincent.weaver@maine.edu
Cc: maria.n.dimakopoulou@gmail.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1389176153-3128-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds a new field to the struct perf_event.
It is intended to be used to chain events which are
active (enabled). It helps in the hardware layer
for PMUs which do not have actual counter restrictions, i.e.,
free running read-only counters. Active events are chained
as opposed to being tracked via the counter they use.
To save space we use a union with hlist_entry as both
are mutually exclusive (suggested by Jiri Olsa).
Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: zheng.z.yan@intel.com
Cc: bp@alien8.de
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1384275531-10892-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a generic qualifier for transaction events, as a new sample
type that returns a flag word. This is particularly useful
for qualifying aborts: to distinguish aborts which happen
due to asynchronous events (like conflicts caused by another
CPU) versus instructions that lead to an abort.
The tuning strategies are very different for those cases,
so it's important to distinguish them easily and early.
Since it's inconvenient and inflexible to filter for this
in the kernel we report all the events out and allow
some post processing in user space.
The flags are based on the Intel TSX events, but should be fairly
generic and mostly applicable to other HTM architectures too. In addition
to various flag words there's also reserved space to report an
program supplied abort code. For TSX this is used to distinguish specific
classes of aborts, like a lock busy abort when doing lock elision.
Flags:
Elision and generic transactions (ELISION vs TRANSACTION)
(HLE vs RTM on TSX; IBM etc. would likely only use TRANSACTION)
Aborts caused by current thread vs aborts caused by others (SYNC vs ASYNC)
Retryable transaction (RETRY)
Conflicts with other threads (CONFLICT)
Transaction write capacity overflow (CAPACITY WRITE)
Transaction read capacity overflow (CAPACITY READ)
Transactions implicitely aborted can also return an abort code.
This can be used to signal specific events to the profiler. A common
case is abort on lock busy in a RTM eliding library (code 0xff)
To handle this case we include the TSX abort code
Common example aborts in TSX would be:
- Data conflict with another thread on memory read.
Flags: TRANSACTION|ASYNC|CONFLICT
- executing a WRMSR in a transaction. Flags: TRANSACTION|SYNC
- HLE transaction in user space is too large
Flags: ELISION|SYNC|CAPACITY-WRITE
The only flag that is somewhat TSX specific is ELISION.
This adds the perf core glue needed for reporting the new flag word out.
v2: Add MEM/MISC
v3: Move transaction to the end
v4: Separate capacity-read/write and remove misc
v5: Remove _SAMPLE. Move abort flags to 32bit. Rename
transaction to txn
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1379688044-14173-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While auditing the list_entry usage due to a trinity bug I found that
perf_pmu_migrate_context violates the rules for
perf_event::event_entry.
The problem is that perf_event::event_entry is a RCU list element, and
hence we must wait for a full RCU grace period before re-using the
element after deletion.
Therefore the usage in perf_pmu_migrate_context() which re-uses the
entry immediately is broken. For now introduce another list_head into
perf_event for this specific usage.
This doesn't actually fix the trinity report because that never goes
through this code.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-mkj72lxagw1z8fvjm648iznw@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 spinlock changes from Ingo Molnar:
"The biggest change here are paravirtualized ticket spinlocks (PV
spinlocks), which bring a nice speedup on various benchmarks.
The KVM host side will come to you via the KVM tree"
* 'x86-spinlocks-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/kvm/guest: Fix sparse warning: "symbol 'klock_waiting' was not declared as static"
kvm: Paravirtual ticketlocks support for linux guests running on KVM hypervisor
kvm guest: Add configuration support to enable debug information for KVM Guests
kvm uapi: Add KICK_CPU and PV_UNHALT definition to uapi
xen, pvticketlock: Allow interrupts to be enabled while blocking
x86, ticketlock: Add slowpath logic
jump_label: Split jumplabel ratelimit
x86, pvticketlock: When paravirtualizing ticket locks, increment by 2
x86, pvticketlock: Use callee-save for lock_spinning
xen, pvticketlocks: Add xen_nopvspin parameter to disable xen pv ticketlocks
xen, pvticketlock: Xen implementation for PV ticket locks
xen: Defer spinlock setup until boot CPU setup
x86, ticketlock: Collapse a layer of functions
x86, ticketlock: Don't inline _spin_unlock when using paravirt spinlocks
x86, spinlock: Replace pv spinlocks with pv ticketlocks
If PERF_SAMPLE_BRANCH_STACK is enabled then samples are returned
with the format { u64 from, to, flags } but the flags layout
is not specified.
This field has the type struct perf_branch_entry; move this
definition into include/uapi/linux/perf_event.h so users can
access these fields.
This is similar to the existing inclusion of perf_mem_data_src in
the include/uapi/linux/perf_event.h file.
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1308231544420.1889@vincent-weaver-1.um.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit b202952075 ("perf, core: Rate limit
perf_sched_events jump_label patching") introduced rate limiting
for jump label disabling. The changes were made in the jump label code
in order to be more widely available and to keep things tidier. This is
all fine, except now jump_label.h includes linux/workqueue.h, which
makes it impossible to include jump_label.h from anything that
workqueue.h needs. For example, it's now impossible to include
jump_label.h from asm/spinlock.h, which is done in proposed
pv-ticketlock patches. This patch splits out the rate limiting related
changes from jump_label.h into a new file, jump_label_ratelimit.h, to
resolve the issue.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Link: http://lkml.kernel.org/r/1376058122-8248-10-git-send-email-raghavendra.kt@linux.vnet.ibm.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.
[1] https://lkml.org/lkml/2013/5/20/589
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Pull scheduler updates from Ingo Molnar:
"The main changes:
- load-calculation cleanups and improvements, by Alex Shi
- various nohz related tidying up of statisics, by Frederic
Weisbecker
- factor out /proc functions to kernel/sched/proc.c, by Paul
Gortmaker
- simplify the RT policy scheduler, by Kirill Tkhai
- various fixes and cleanups"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
sched/debug: Remove CONFIG_FAIR_GROUP_SCHED mask
sched/debug: Fix formatting of /proc/<PID>/sched
sched: Fix typo in struct sched_avg member description
sched/fair: Fix typo describing flags in enqueue_entity
sched/debug: Add load-tracking statistics to task
sched: Change get_rq_runnable_load() to static and inline
sched/tg: Remove tg.load_weight
sched/cfs_rq: Change atomic64_t removed_load to atomic_long_t
sched/tg: Use 'unsigned long' for load variable in task group
sched: Change cfs_rq load avg to unsigned long
sched: Consider runnable load average in move_tasks()
sched: Compute runnable load avg in cpu_load and cpu_avg_load_per_task
sched: Update cpu load after task_tick
sched: Fix sleep time double accounting in enqueue entity
sched: Set an initial value of runnable avg for new forked task
sched: Move a few runnable tg variables into CONFIG_SMP
Revert "sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking"
sched: Don't mix use of typedef ctl_table and struct ctl_table
sched: Remove WARN_ON(!sd) from init_sched_groups_power()
sched: Fix memory leakage in build_sched_groups()
...
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Merge tag 'v3.10' into sched/core
Merge in a recent upstream commit:
c2853c8df5 include/linux/math64.h: add div64_ul()
because:
72a4cf20cb sched: Change cfs_rq load avg to unsigned long
relies on it.
[ We don't rebase sched/core for this, because the handful of
followup commits after the broken commit are not behavioral
changes so are unlikely to be needed during bisection. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Kan Liang