perf tools: Add dynamic sort key for tracepoint events
The existing sort keys are less useful for tracepoint events in that
they are always sampled at the same place, the function where the
tracepoint is located.
For example, a 'perf report' on sched:sched_switch event looks like the
following:
# Overhead Command Shared Object Symbol
# ........ ............... ................ ..............
#
47.22% swapper [kernel.vmlinux] [k] __schedule
21.67% transmission-gt [kernel.vmlinux] [k] __schedule
8.23% netctl-auto [kernel.vmlinux] [k] __schedule
5.53% kworker/0:1H [kernel.vmlinux] [k] __schedule
1.98% Xephyr [kernel.vmlinux] [k] __schedule
1.33% irq/33-iwlwifi [kernel.vmlinux] [k] __schedule
1.17% wpa_cli [kernel.vmlinux] [k] __schedule
1.13% rcu_preempt [kernel.vmlinux] [k] __schedule
0.85% ksoftirqd/0 [kernel.vmlinux] [k] __schedule
0.77% Timer [kernel.vmlinux] [k] __schedule
In fact, tracepoints have meaningful information in their fields but
there's no way to use in 'perf report' currently. The dynamic sort keys
are introduced in this patc to overcome this limitation.
The sched:sched_switch events have following fields:
# sudo cat /sys/kernel/debug/tracing/events/sched/sched_switch/format
name: sched_switch
ID: 268
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:char prev_comm[16]; offset:8; size:16; signed:1;
field:pid_t prev_pid; offset:24; size:4; signed:1;
field:int prev_prio; offset:28; size:4; signed:1;
field:long prev_state; offset:32; size:8; signed:1;
field:char next_comm[16]; offset:40; size:16; signed:1;
field:pid_t next_pid; offset:56; size:4; signed:1;
field:int next_prio; offset:60; size:4; signed:1;
print fmt: "prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==>
next_comm=%s next_pid=%d next_prio=%d",
REC->prev_comm, REC->prev_pid, REC->prev_prio,
REC->prev_state & (2048-1) ? __print_flags(REC->prev_state & (2048-1),
"|", { 1, "S"} , { 2, "D" }, { 4, "T" }, { 8, "t" }, { 16, "Z" }, { 32, "X" },
{ 64, "x" }, { 128, "K"}, { 256, "W" }, { 512, "P" }, { 1024, "N" }) : "R",
REC->prev_state & 2048 ? "+" : "", REC->next_comm, REC->next_pid, REC->next_prio
With dynamic sort keys, you can use <event.field> as a sort key. Those
dynamic keys are checked and created on demand. For instance, below is
to sort by next_pid field output on the same data file:
$ perf report -s comm,sched:sched_switch.next_pid --stdio
...
# Overhead Command next_pid
# ........ ............... ..........
#
21.23% transmission-gt 0
20.86% swapper 17773
6.62% netctl-auto 0
5.25% swapper 109
5.21% kworker/0:1H 0
1.98% Xephyr 0
1.98% swapper 6524
1.98% swapper 27478
1.37% swapper 27476
1.17% swapper 233
Multiple dynamic sort keys are also supported:
$ perf report -s comm,sched:sched_switch.next_pid,sched:sched_switch.next_comm --stdio
...
# Overhead Command next_pid next_comm
# ........ ............... .......... ................
#
20.86% swapper 17773 transmission-gt
9.64% transmission-gt 0 swapper/0
9.16% transmission-gt 0 swapper/2
5.25% swapper 109 kworker/0:1H
5.21% kworker/0:1H 0 swapper/0
2.14% netctl-auto 0 swapper/2
1.98% netctl-auto 0 swapper/0
1.98% swapper 6524 Xephyr
1.98% swapper 27478 netctl-auto
1.78% transmission-gt 0 swapper/3
1.53% Xephyr 0 swapper/0
1.29% netctl-auto 0 swapper/1
1.29% swapper 27476 netctl-auto
1.21% netctl-auto 0 swapper/3
1.17% swapper 233 irq/33-iwlwifi
Note that pid 0 exists for each cpu so have comm of 'swapper/N'.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1450804030-29193-6-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
c7c2a5e40f