From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753159AbcLLOxR (ORCPT ); Mon, 12 Dec 2016 09:53:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41034 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751505AbcLLOxQ (ORCPT ); Mon, 12 Dec 2016 09:53:16 -0500 Date: Mon, 12 Dec 2016 15:53:12 +0100 From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , David Ahern , Namhyung Kim , Peter Zijlstra , lkml , Ingo Molnar Subject: Re: [PATCH 4/5] perf tools: Allow to ignore missing pid Message-ID: <20161212145312.GA28361@krava> References: <1481538943-21874-1-git-send-email-jolsa@kernel.org> <1481538943-21874-5-git-send-email-jolsa@kernel.org> <20161212143209.GB5650@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161212143209.GB5650@kernel.org> User-Agent: Mutt/1.7.1 (2016-10-04) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 12 Dec 2016 14:53:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 12, 2016 at 11:32:09AM -0300, Arnaldo Carvalho de Melo wrote: > Em Mon, Dec 12, 2016 at 11:35:42AM +0100, Jiri Olsa escreveu: > > Adding perf_evsel::ignore_missing_cpu_thread bool. > > > > When set true, it allows perf to ignore error of missing > > pid of perf event syscall. > > > > We remove missing thread id from the thread_map, so the > > rest of the processing like ioctl and mmap won't get > > disturbed with -1 fd > > What was the test performed? I tried it here the following while doing > a 'make -j4 allmodconfig' in the background, i.e. tons of threads coming > and going, and I sometimes get: > > [root@jouet ~]# perf record -u acme > Error: > The sys_perf_event_open() syscall returned with 3 (No such process) for > event (cycles:ppp). > /bin/dmesg may provide additional information. > No CONFIG_PERF_EVENTS=y kernel support configured? I dont think it's fast enough (start/stop) to hit the race, I've got best results with having on background this: while :; do /usr/bin/true; done jirka