Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756294Ab3EQOkC (ORCPT ); Fri, 17 May 2013 10:40:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9499 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756233Ab3EQOkB (ORCPT ); Fri, 17 May 2013 10:40:01 -0400 Date: Fri, 17 May 2013 16:39:44 +0200 From: Jiri Olsa To: Namhyung Kim Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Namhyung Kim , LKML , David Ahern , Stephane Eranian Subject: Re: [PATCH 5/9] perf report: Don't be bothered with locking when adding hist entries Message-ID: <20130517143944.GF3848@krava.brq.redhat.com> References: <1368497347-9628-1-git-send-email-namhyung@kernel.org> <1368497347-9628-6-git-send-email-namhyung@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1368497347-9628-6-git-send-email-namhyung@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1639 Lines: 37 On Tue, May 14, 2013 at 11:09:03AM +0900, Namhyung Kim wrote: > From: Namhyung Kim > > 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 > --- > tools/perf/builtin-report.c | 4 ---- > 1 file changed, 4 deletions(-) nice :) Acked-by: Jiri Olsa jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/