Messages in this thread | | | Date | Fri, 17 May 2013 16:39:44 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 5/9] perf report: Don't be bothered with locking when adding hist entries |
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On Tue, May 14, 2013 at 11:09:03AM +0900, Namhyung Kim wrote: > From: Namhyung Kim <namhyung.kim@lge.com> > > The perf report is single-threaded, so no need to grab a lock. > Although the fast path of pthread_mutex_[un]lock() is very fast, > there's ~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> > --- > tools/perf/builtin-report.c | 4 ---- > 1 file changed, 4 deletions(-)
nice :)
Acked-by: Jiri Olsa <jolsa@redhat.com>
jirka
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