Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756012AbaDVNhg (ORCPT ); Tue, 22 Apr 2014 09:37:36 -0400 Received: from mail-oa0-f52.google.com ([209.85.219.52]:57243 "EHLO mail-oa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751689AbaDVNhb (ORCPT ); Tue, 22 Apr 2014 09:37:31 -0400 MIME-Version: 1.0 In-Reply-To: <20140422133242.GF1104@krava.brq.redhat.com> References: <20140421160655.GA4201@quad> <20140422133242.GF1104@krava.brq.redhat.com> Date: Tue, 22 Apr 2014 15:37:30 +0200 Message-ID: Subject: Re: [PATCH] perf tools: fix processing of pid/tid for mmap records From: Stephane Eranian To: Jiri Olsa Cc: LKML , Arnaldo Carvalho de Melo , Peter Zijlstra , "mingo@elte.hu" , Namhyung Kim , David Ahern Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jiri, On Tue, Apr 22, 2014 at 3:32 PM, Jiri Olsa wrote: > hi, > > On Mon, Apr 21, 2014 at 06:06:55PM +0200, Stephane Eranian wrote: >> perf tools: fix processing of pid/tid for mmap records > > extra description line ^^^ > >> >> Mmaps are global to a process (always). Processing them >> per-thread was causing some serious issues in case mmaps >> would overlap. The overlap fixups would only occur in the >> context of the thread which generated the overlapping >> mmap. But that was cause issues later on when a sample >> from another thread would fall into that overlapping >> mmap. >> >> The solution to the problem is to handle ALL mmaps as >> occurring in the master thread (pid = tid) and then to >> lookup for thread map using pid as the tid argument. >> This is how samples are looking up for the thread map >> already (notice pid passed twice): >> >> int perf_event__preprocess_sample(const union perf_event *event, >> struct machine *machine, >> struct addr_location *al, >> struct perf_sample *sample) >> { >> struct thread *thread = machine__findnew_thread(machine, sample->pid, >> sample->pid); >> } >> >> Without this fix, some samples in overlapping regions >> may not be symbolized. > > could you please take a look on following patchset: > http://marc.info/?l=linux-kernel&m=139749074531132&w=2 > > this makes the map groups shared within the process, > so it should fix above issue as well > It could probably solve my problem. I will try it out. I am wondering why the tid was taken into consideration in the first place when looking for maps? why was pid not enough? -- 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/