Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755256Ab3IMMqX (ORCPT ); Fri, 13 Sep 2013 08:46:23 -0400 Received: from mail-ea0-f177.google.com ([209.85.215.177]:49152 "EHLO mail-ea0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751901Ab3IMMqW (ORCPT ); Fri, 13 Sep 2013 08:46:22 -0400 Date: Fri, 13 Sep 2013 14:46:18 +0200 From: Frederic Weisbecker To: Namhyung Kim Cc: LKML , Jiri Olsa , David Ahern , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Stephane Eranian Subject: Re: [PATCH 0/4] perf tools: New comm infrastructure Message-ID: <20130913124616.GC4844@somewhere> References: <1379017783-27032-1-git-send-email-fweisbec@gmail.com> <87y571qlj1.fsf@sejong.aot.lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87y571qlj1.fsf@sejong.aot.lge.com> 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: 3653 Lines: 73 On Fri, Sep 13, 2013 at 03:32:34PM +0900, Namhyung Kim wrote: > Hi Frederic, > > On Thu, 12 Sep 2013 22:29:39 +0200, Frederic Weisbecker wrote: > > The way we handle hists sorted by comm is to first gather them by tid then > > in the end merge/collapse hists that end up with the same comm. > > > > But merging hists has shown some performances issues, especially with callchain > > where the operation can be very heavy. > > > > So this new comm infrastructure aims at removing comm collapses. It brings > > two features: > > > > 1) Keep track of comms lifecycle by storing timestamps when the comms > > are set. This way we can map the precise comm to any thread:time couple. > > This only works if the PERF_SAMPLE_ID comes along comm and fork events, > > otherwise we only track the latest comm set for a thread. > > > > This can provide us more precise comm sorted hists by distinguishing pre and > > post exec timeframes into seperate hists for a single thread. > > > > Note that although the comm infrastructure is ready to do this, I haven't > > yet made the perf tools support that. It's a TODO entry. > > > > > > 2) Allocate comms only once instead of duplicating them for all threads sharing > > a same one. Two threads having the same comm should now point to the same string. > > As a result we can compare hists thread comm by address. > > > > The big upside is that we can now live sort comm hists instead of collapsing > > them in the end of the processing. > > > > I've seen very nice performance results on perf report. Roughly a 1.5x to 2x > > on perf report default stdio output with callchains. > > > > You can try this branch: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git > > perf/comm > > > > May be merging that with Namhyung callchains patches could provide some > > cumulative nice results. > > I got this: > > ui/browsers/hists.c: In function ‘hists__browser_title’: > ui/browsers/hists.c:1258:10: error: passing argument 1 of ‘thread__comm_curr’ discards ‘const’ qualifier from pointer target type [-Werror] > In file included from ui/browsers/../../util/sort.h:24:0, > from ui/browsers/hists.c:11: > ui/browsers/../../util/thread.h:39:13: note: expected ‘struct thread *’ but argument is of type ‘const struct thread *’ > ui/browsers/hists.c: In function ‘perf_evsel__hists_browse’: > ui/browsers/hists.c:1581:9: error: passing argument 1 of ‘thread__comm_curr’ discards ‘const’ qualifier from pointer target type [-Werror] > In file included from ui/browsers/../../util/sort.h:24:0, > from ui/browsers/hists.c:11: > ui/browsers/../../util/thread.h:39:13: note: expected ‘struct thread *’ but argument is of type ‘const struct thread *’ > ui/browsers/hists.c:1704:10: error: passing argument 1 of ‘thread__comm_curr’ discards ‘const’ qualifier from pointer target type [-Werror] > In file included from ui/browsers/../../util/sort.h:24:0, > from ui/browsers/hists.c:11: > ui/browsers/../../util/thread.h:39:13: note: expected ‘struct thread *’ but argument is of type ‘const struct thread *’ > cc1: all warnings being treated as errors > make: *** [ui/browsers/hists.o] Error 1 > make: *** Waiting for unfinished jobs.... Oops, I'm missing the libs to build the ui, so I didn't see this. Will fix, thanks! > > Thanks, > Namhyung -- 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/