This is another attempt for the reduction of the latency at the start
of a USB audio playback stream. The first attempt in the commit
9ce650a75a caused an unexpected regression (a deadlock with pipewire
usage) and was later reverted by the commit 4b820e167b. The devils
are always living in details, of course; the cause of the deadlock was
the call of snd_pcm_period_elapsed() inside prepare_playback_urb()
callback. In the original code, this callback is never called from
the stream lock context as it's driven solely from the URB complete
callback. Along with the movement of the URB submission into the
trigger START, this prepare call may be also executed in the stream
lock context, hence it deadlocked with the another lock in
snd_pcm_period_elapsed(). (Note that this happens only conditionally
with a small period size that matches with the URB buffer length,
which was a reason I overlooked during my tests. Also, the problem
wasn't seen in the capture stream because the capture stream handles
the period-elapsed only at retire callback that isn't executed at the
trigger.)
If it were only about avoiding the deadlock, it'd be possible to use
snd_pcm_period_elapsed_under_stream_lock() as a solution. However, in
general, the period elapsed notification must be sent after the actual
stream start, and replacing the call wouldn't satisfy the pattern.
A better option is to delay the notification after the stream start
procedure finished, instead. In the case of USB framework, one of the
fitting place would be the complete callback of the first URB.
So, as a workaround of the deadlock and the order fixes above, in
addition to the re-applying the changes in the commit 9ce650a75a,
this patch introduces a new flag indicating the delayed period-elapsed
handling and sets it under the possible deadlock condition
(i.e. prepare callback being called before subs->running is set).
Once when the flag is set, the period-elapsed call is handled at a
later URB complete call instead.
As a reference for the original motivation for the low-latency change,
I cite here again:
| USB-audio driver behaves a bit strangely for the playback stream --
| namely, it starts sending silent packets at PCM prepare state while
| the actual data is submitted at first when the trigger START is
| kicked off. This is a workaround for the behavior where URBs are
| processed too quickly at the beginning. That is, if we start
| submitting URBs at trigger START, the first few URBs will be
| immediately completed, and this would result in the immediate
| period-elapsed calls right after the start, which may confuse
| applications.
|
| OTOH, submitting the data after silent URBs would, of course, result
| in a certain delay of the actual data processing, and this is rather
| more serious problem on modern systems, in practice.
|
| This patch tries to revert the workaround and lets the URB
| submission starting at PCM trigger for the playback again. As far
| as I've tested with various backends (native ALSA, PA, JACK, PW), I
| haven't seen any problems (famous last words :)
|
| Note that the capture stream handling needs no such workaround,
| since the capture is driven per received URB.
Link: https://lore.kernel.org/r/4e71531f-4535-fd46-040e-506a3c256bbd@marcan.st
Link: https://lore.kernel.org/r/s5hbl7li0fe.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20210707112447.27485-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Make tests to be two binaries 'tests_static' and 'tests_shared', so the
maintenance is easier.
Adding tests under libperf build system, so we define all the flags just
once.
Adding make-tests tule to just compile tests without running them.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Link: http://lore.kernel.org/lkml/20210706151704.73662-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The Intel PT decoder limits the number of unconditional branches (e.g.
jmps) decoded without consuming any trace packets. Generally, a loop
needs a conditional branch which generates a TNT packet, whereas a "ret"
instruction will generate a TIP or TNT packet. So exceeding the limit is
assumed to be a never-ending loop, which can happen if there has been a
decoding error putting the decoder at the wrong place in the code.
Up until now, the limit of 10000 has been enough but some analytic
purposes have been reported to exceed that.
Increase the limit to 100000, and make it configurable via perf config
intel-pt.max-loops. Also amend the "Never-ending loop" message to
mention the configuration entry.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20210701175132.3977-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Commit 48a1f56526 ("perf script python: Add more PMU fields to
event handler dict") added functionality to report fields like weight,
iregs, uregs etc via perf report. That commit predefined buffer size to
512 bytes to print those fields.
But in PowerPC, since we added extended regs support in:
068aeea377 ("perf powerpc: Support exposing Performance Monitor Counter SPRs as part of extended regs")
d735599a06 ("powerpc/perf: Add extended regs support for power10 platform")
Now iregs can carry more bytes of data and this predefined buffer size
can result to data loss in perf script output.
This patch resolves this issue by making the buffer size dynamic, based
on the number of registers needed to print. It also changes the
regs_map() return type from int to void, as it is not being used by the
set_regs_in_dict(), its only caller.
Fixes: 068aeea377 ("perf powerpc: Support exposing Performance Monitor Counter SPRs as part of extended regs")
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lore.kernel.org/lkml/20210628062341.155839-1-kjain@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The install perf_dlfilter.h patch included what seems to be a typo in
the Makefile.perf, which changed the location of the trace link from
'$(DESTDIR_SQ)$(bindir_SQ)/trace' to '$(DESTDIR_SQ)$(dir_SQ)/trace'.
This reverts it back to the correct location.
Fixes: 0beb218315 ("perf build: Install perf_dlfilter.h")
Signed-off-by: Justin M. Forbes <jforbes@fedoraproject.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Justin M. Forbes <jmforbes@linuxtx.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210706185952.116121-1-jforbes@fedoraproject.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
ASan reports a heap-buffer-overflow in elf_sec__is_text when using perf-top.
The bug is caused by the fact that secstrs is built from runtime_ss, while
shdr is built from syms_ss if shdr.sh_type != SHT_NOBITS. Therefore, they
point to two different ELF files.
This patch renames secstrs to secstrs_run and adds secstrs_sym, so that
the correct secstrs is chosen depending on shdr.sh_type.
$ ASAN_OPTIONS=abort_on_error=1:disable_coredump=0:unmap_shadow_on_exit=1 ./perf top
=================================================================
==363148==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61300009add6 at pc 0x00000049875c bp 0x7f4f56446440 sp 0x7f4f56445bf0
READ of size 1 at 0x61300009add6 thread T6
#0 0x49875b in StrstrCheck(void*, char*, char const*, char const*) (/home/user/linux/tools/perf/perf+0x49875b)
#1 0x4d13a2 in strstr (/home/user/linux/tools/perf/perf+0x4d13a2)
#2 0xacae36 in elf_sec__is_text /home/user/linux/tools/perf/util/symbol-elf.c:176:9
#3 0xac3ec9 in elf_sec__filter /home/user/linux/tools/perf/util/symbol-elf.c:187:9
#4 0xac2c3d in dso__load_sym /home/user/linux/tools/perf/util/symbol-elf.c:1254:20
#5 0x883981 in dso__load /home/user/linux/tools/perf/util/symbol.c:1897:9
#6 0x8e6248 in map__load /home/user/linux/tools/perf/util/map.c:332:7
#7 0x8e66e5 in map__find_symbol /home/user/linux/tools/perf/util/map.c:366:6
#8 0x7f8278 in machine__resolve /home/user/linux/tools/perf/util/event.c:707:13
#9 0x5f3d1a in perf_event__process_sample /home/user/linux/tools/perf/builtin-top.c:773:6
#10 0x5f30e4 in deliver_event /home/user/linux/tools/perf/builtin-top.c:1197:3
#11 0x908a72 in do_flush /home/user/linux/tools/perf/util/ordered-events.c:244:9
#12 0x905fae in __ordered_events__flush /home/user/linux/tools/perf/util/ordered-events.c:323:8
#13 0x9058db in ordered_events__flush /home/user/linux/tools/perf/util/ordered-events.c:341:9
#14 0x5f19b1 in process_thread /home/user/linux/tools/perf/builtin-top.c:1109:7
#15 0x7f4f6a21a298 in start_thread /usr/src/debug/glibc-2.33-16.fc34.x86_64/nptl/pthread_create.c:481:8
#16 0x7f4f697d0352 in clone ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
0x61300009add6 is located 10 bytes to the right of 332-byte region [0x61300009ac80,0x61300009adcc)
allocated by thread T6 here:
#0 0x4f3f7f in malloc (/home/user/linux/tools/perf/perf+0x4f3f7f)
#1 0x7f4f6a0a88d9 (/lib64/libelf.so.1+0xa8d9)
Thread T6 created by T0 here:
#0 0x464856 in pthread_create (/home/user/linux/tools/perf/perf+0x464856)
#1 0x5f06e0 in __cmd_top /home/user/linux/tools/perf/builtin-top.c:1309:6
#2 0x5ef19f in cmd_top /home/user/linux/tools/perf/builtin-top.c:1762:11
#3 0x7b28c0 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
#4 0x7b119f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
#5 0x7b2423 in run_argv /home/user/linux/tools/perf/perf.c:409:2
#6 0x7b0c19 in main /home/user/linux/tools/perf/perf.c:539:3
#7 0x7f4f696f7b74 in __libc_start_main /usr/src/debug/glibc-2.33-16.fc34.x86_64/csu/../csu/libc-start.c:332:16
SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/user/linux/tools/perf/perf+0x49875b) in StrstrCheck(void*, char*, char const*, char const*)
Shadow bytes around the buggy address:
0x0c268000b560: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b570: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b580: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b590: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c268000b5a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c268000b5b0: 00 00 00 00 00 00 00 00 00 04[fa]fa fa fa fa fa
0x0c268000b5c0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
0x0c268000b5d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c268000b5e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c268000b5f0: 07 fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b600: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==363148==ABORTING
Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Remi Bernon <rbernon@codeweavers.com>
Link: http://lore.kernel.org/lkml/20210621222108.196219-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If the disasm is empty, 's' should fail. Instead it seemingly works,
hiding the empty lines and causing an assertion error on the next time
annotate is called (from within perf report).
The problem is caused by a buffer overflow, caused by a wrong exit
condition in annotate_browser__find_next_asm_line, which checks
browser->b.top instead of browser->b.entries.
This patch fixes the issue, making annotate_browser__toggle_source
fail if the disasm is empty (nothing happens to the user).
Fixes: 6de249d66d ("perf annotate: Allow 's' on source code lines")
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Liška <mliska@suse.cz>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210705161524.72953-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In Fedora34, libc-2.33.so has both .dynsym and .symtab sections and
most of (not all) symbols moved to .dynsym. In this case, perf only
decode the symbols in .symtab, and perf probe can not list up the
functions in the library.
To fix this issue, decode both .symtab and .dynsym sections.
Without this fix,
-----
$ ./perf probe -x /usr/lib64/libc-2.33.so -F
@plt
@plt
calloc@plt
free@plt
malloc@plt
memalign@plt
realloc@plt
-----
With this fix.
-----
$ ./perf probe -x /usr/lib64/libc-2.33.so -F
@plt
@plt
a64l
abort
abs
accept
accept4
access
acct
addmntent
-----
Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stefan Liebler <stli@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Link: http://lore.kernel.org/lkml/162532652681.393143.10163733179955267999.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix debuginfo__new() to set the build-id to dso before
dso__read_binary_type_filename() so that it can find
DSO_BINARY_TYPE__BUILDID_DEBUGINFO debuginfo correctly.
However, this may not change the result, because elfutils (libdwfl) has
its own debuginfo finder. With/without this patch, the perf probe
correctly find the debuginfo file.
This is just a failsafe and keep code's sanity (if you use
dso__read_binary_type_filename(), you must set the build-id to the dso.)
Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Masami Hiramatsu <mhriamat@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stefan Liebler <stli@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Link: http://lore.kernel.org/lkml/162532651863.393143.11692691321219235810.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On the IO submission path, blk_account_io_start() may interrupt
the system interruption. When the interruption returns, the value
of part->stamp may have been updated by other cores, so the time
value collected before the interruption may be less than part->
stamp. So when this happens, we should do nothing to make io_ticks
more accurate? For kernels less than 5.0, this may cause io_ticks
to become smaller, which in turn may cause abnormal ioutil values.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/1625521646-1069-1-git-send-email-brookxu.cn@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When 'SB_HW_16' check fails, the error code -ENODEV instead of 0 should be
returned, which is the same as that returned when 'WSS_HW_CMI8330' check
fails.
Fixes: 43bcd973d6 ("[ALSA] Add snd_card_set_generic_dev() call to ISA drivers")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210707074051.2663-1-thunder.leizhen@huawei.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Otherwise, writeback is going to fall in a loop to flush dirty inode forever
before getting SBI_CLOSING.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
In error cases the dentry may be NULL.
Before 20798dfe24, the encoder also checked dentry and
d_really_is_positive(dentry), but that looks like overkill to me--zero
status should be enough to guarantee a positive dentry.
This isn't the first time we've seen an error-case NULL dereference
hidden in the initialization of a local variable in an xdr encoder. But
I went back through the other recent rewrites and didn't spot any
similar bugs.
Reported-by: JianHong Yin <jiyin@redhat.com>
Reviewed-by: Chuck Lever III <chuck.lever@oracle.com>
Fixes: 20798dfe24 ("NFSD: Update the NFSv3 GETACL result encoder...")
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The double copy of the string is a mistake, plus __assign_str()
uses strlen(), which is wrong to do on a string that isn't
guaranteed to be NUL-terminated.
Fixes: 6019ce0742 ("NFSD: Add a tracepoint to record directory entry encoding")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The pointer 'this' is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
When flushing out the unstable file writes as part of a COMMIT call, try
to perform most of of the data writes and waits outside the semaphore.
This means that if the client is sending the COMMIT as part of a memory
reclaim operation, then it can continue performing I/O, with contention
for the lock occurring only once the data sync is finished.
Fixes: 5011af4c69 ("nfsd: Fix stable writes")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Add a .h file containing xdr_stream-based XDR helpers common to both
NLMv3 and NLMv4.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
To enable xdr_stream-based encoding and decoding, create a bespoke
RPC dispatch function for the lockd service.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Takashi Iwai