From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753143AbbJWQR7 (ORCPT ); Fri, 23 Oct 2015 12:17:59 -0400 Received: from mail.kernel.org ([198.145.29.136]:40774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753081AbbJWQR4 (ORCPT ); Fri, 23 Oct 2015 12:17:56 -0400 Date: Fri, 23 Oct 2015 13:17:49 -0300 From: Arnaldo Carvalho de Melo To: pi3orama Cc: Wang Nan , linux-kernel@vger.kernel.org, Alexei Starovoitov , Peter Zijlstra , Li Zefan Subject: Re: [RFC PATCH] perf tools: Don't set inherit bit for system wide evsel Message-ID: <20151023161749.GF27006@kernel.org> References: <1445597029-133332-1-git-send-email-wangnan0@huawei.com> <20151023135141.GD27006@kernel.org> <3E5B2C7C-BD19-4B61-AEDC-D1E2CFE0D7D2@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3E5B2C7C-BD19-4B61-AEDC-D1E2CFE0D7D2@163.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, Oct 23, 2015 at 09:58:20PM +0800, pi3orama escreveu: > > > 发自我的 iPhone > > > 在 2015年10月23日，下午9:51，Arnaldo Carvalho de Melo 写道： > > > > Em Fri, Oct 23, 2015 at 10:43:49AM +0000, Wang Nan escreveu: > >> Inherit bit is useless for a system wide evsel [1]. Further kernel > >> improvements are giving more constrain [2] on inherit events. This > >> patch set inherit bit to 0 to avoid potential constrains. > >> > >> [1] http://lkml.kernel.org/r/20151022124142.GQ17308@twins.programming.kicks-ass.net > >> [2] http://lkml.kernel.org/r/1445559014-4667-1-git-send-email-ast@kernel.org > >> > >> Signed-off-by: Wang Nan > >> Cc: Arnaldo Carvalho de Melo > >> Cc: Alexei Starovoitov > >> Cc: Peter Zijlstra > >> Cc: Li Zefan > >> Cc: pi3orama@163.com > >> Link: http://lkml.kernel.org/n/ebpf-0tgilipxoo6fiebcxu3ft866@git.kernel.org > >> --- > >> > >> evsel->system_wide doesn't correct reflect whether this evsel is system > >> wide or not, so checks pid when invoking perf_event_open, and it is > >> always correct. > > > > Can't we do this at perf_evlist__config() or perf_evsel__config() time? > > perf_evlist_config() is excluded because perf record doesn't use it. Yeah, we need to make it use it :-\ > > We have record_opts at perf_evsel__config() time and I think we should > > leave changing the attr at perf_evsel__open() time for feature > > fallbacks, i.e. something we will only know when trying to use, which is > > different from this inherit-on-syswide case, that we know far in advance > > we will not need. > > I tried to set this bit based on evsel->system_wide but it seems not reliable > as it should be, so I was wondering whether it is designed for other use. I will look > into this next week. Ok, thanks in advance, lemme go back looking at eBPF :-) - Arnaldo