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| author | Namhyung Kim <namhyung.kim@lge.com> | 2013-05-14 11:09:03 +0900 |
|---|---|---|
| committer | Chanho Park <chanho61.park@samsung.com> | 2014-11-18 11:43:31 +0900 |
| commit | 13d39f6fcd5d0352733c8654172d7be87fa2759c (patch) | |
| tree | ab4483dd10e19036515137b06c90c4063501908c /tools | |
| parent | 42562805248b4ddb229c46fe0aba2d81edffebc2 (diff) | |
| download | linux-3.10-13d39f6fcd5d0352733c8654172d7be87fa2759c.tar.gz linux-3.10-13d39f6fcd5d0352733c8654172d7be87fa2759c.tar.bz2 linux-3.10-13d39f6fcd5d0352733c8654172d7be87fa2759c.zip | |
perf report: Don't bother locking when adding hist entries
The 'perf report'command is single-threaded, so no need to grab a lock.
Although the fast path of pthread_mutex_[un]lock() is very fast, there's
a ~3% gain by eliminating it when we have huge sample data.
$ perf record -a -F 100000 -o perf.data.bench -- perf bench sched all
$ perf record -e cycles:upp -o perf.data.before -- \
> perf report -i perf.data.bench --stdio > /dev/null
... apply this patch ...
$ perf record -e cycles:upp -o perf.data.after -- \
> perf report -i perf.data.bench --stdio > /dev/null
$ perf diff perf.data.{before,after} | grep pthread
+0.02% libpthread-2.15.so [.] _pthread_cleanup_push_defer
+0.02% libpthread-2.15.so [.] _pthread_cleanup_pop_restore
0.05% -0.05% perf [.] pthread_mutex_unlock@plt
0.05% -0.05% perf [.] pthread_mutex_lock@plt
1.01% -1.01% libpthread-2.15.so [.] pthread_mutex_lock
1.68% -1.68% libpthread-2.15.so [.] __pthread_mutex_unlock_usercnt
0.05% -0.05% libpthread-2.15.so [.] pthread_mutex_unlock
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1368497347-9628-6-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/builtin-report.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 63febd24e91..0f0cf2472d9 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -312,8 +312,6 @@ static int process_sample_event(struct perf_tool *tool, if (rep->cpu_list && !test_bit(sample->cpu, rep->cpu_bitmap)) return 0; - pthread_mutex_lock(&evsel->hists.lock); - if (sort__mode == SORT_MODE__BRANCH) { ret = perf_report__add_branch_hist_entry(tool, &al, sample, evsel, machine); @@ -332,8 +330,6 @@ static int process_sample_event(struct perf_tool *tool, if (ret < 0) pr_debug("problem incrementing symbol period, skipping event\n"); } - pthread_mutex_unlock(&evsel->hists.lock); - return ret; } |