From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932748Ab1JZLSc (ORCPT ); Wed, 26 Oct 2011 07:18:32 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:64200 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932673Ab1JZLSb (ORCPT ); Wed, 26 Oct 2011 07:18:31 -0400 Date: Wed, 26 Oct 2011 09:18:28 -0200 From: Arnaldo Carvalho de Melo To: Deng-Cheng Zhu Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Paul Mackerras , Ingo Molnar Subject: Re: [RFC PATCH 2/2] tools/perf: Make group_fd static and move its place in __perf_evsel__open() Message-ID: <20111026111828.GB9467@ghostprotocols.net> References: <1319453820-12992-1-git-send-email-dczhu@mips.com> <1319453820-12992-3-git-send-email-dczhu@mips.com> <20111024140328.GA5770@ghostprotocols.net> <20111025152309.GA7623@ghostprotocols.net> <4EA7A7FB.40304@mips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4EA7A7FB.40304@mips.com> X-Url: http://acmel.wordpress.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 Em Wed, Oct 26, 2011 at 02:26:03PM +0800, Deng-Cheng Zhu escreveu: > On 10/25/2011 11:23 PM, Arnaldo Carvalho de Melo wrote: > >Em Mon, Oct 24, 2011 at 12:03:28PM -0200, Arnaldo Carvalho de Melo escreveu: > >>Em Mon, Oct 24, 2011 at 06:57:00PM +0800, Deng-Cheng Zhu escreveu: > >>>__perf_evsel__open() is called per event, it does not work for all the > >>>grouped events at one time. So, currently group_fd will alway be -1 for > >>>+ static int group_fd = -1; > >>> if (!evsel->cgrp) > >>> pid = threads->map[thread]; > >>Lets not do it that way, using statics for this is humm, ugly, IMHO. > >Can you try this patch? > >I tested it with: > >[root@emilia ~]# perf top -e cycles -e instructions --group > Your patch does fix the group fd issue. But to get event grouping > workable, the event state fix is still needed. Please see the discussion Can I have your "Reviewed-by:" or "Tested-by:" tag for this patch then? > here: http://www.spinics.net/lists/mips/msg42190.html > With _only_ your patch applied, I tested with the following commands on > MIPS 74K (4 counters available in total): > > perf stat -g -e > L1-dcache-load-misses,cycles,LLC-load-misses,iTLB-loads,instructions > find / >/dev/null > > I tried to group up to 5 events in the hope of seeing NOSPC error. But > the command didn't fail and output: > > Performance counter stats for 'find /': > > 9300823 L1-dcache-load-misses > cycles > LLC-load-misses > iTLB-loads > instructions > > 8.463207591 seconds time elapsed > > This is due to the event state check in validate_group() filtering out > the grouped events in OFF state. They are in OFF state because we are > running the command with the perf tool as opposed to attaching to an > existing task: > > builtin-stat.c:create_perf_stat_counter(): > > if (target_pid == -1 && target_tid == -1) { > attr->disabled = 1; > attr->enable_on_exec = 1; > } But they should be in OFF state only till the target program gets exec'ed, right? > I suppose X86 has this issue too -- collect_events() in validate_group() > won't do real work in the bottom half of the function. I'm testing that now. - Arnaldo