From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754849Ab1I3CVq (ORCPT ); Thu, 29 Sep 2011 22:21:46 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:46121 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751739Ab1I3CVp (ORCPT ); Thu, 29 Sep 2011 22:21:45 -0400 Date: Thu, 29 Sep 2011 23:21:34 -0300 From: Arnaldo Carvalho de Melo To: David Ahern Cc: Jiri Olsa , a.p.zijlstra@chello.nl, mingo@elte.hu, Stephane Eranian , paulus@samba.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf tools: Exit recording if events have non matching sample type Message-ID: <20110930022134.GB9369@ghostprotocols.net> References: <20110929230613.GA20083@ghostprotocols.net> <4E850056.1090101@gmail.com> <20110930004018.GA9369@ghostprotocols.net> <4E85142C.101@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E85142C.101@gmail.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 Thu, Sep 29, 2011 at 06:58:20PM -0600, David Ahern escreveu: > On 09/29/2011 06:40 PM, Arnaldo Carvalho de Melo wrote: > > This comes from time to time: > > > > http://us.generation-nt.com/answer/bug-perf-event-sampling-buffer-format-cannot-handle-multi-event-sampling-help-202985832.html > > > > The whole point of sample_type is to ask for just what is needed for > > some specific event so that we reduce the per sample footprint. > > > > So we allow for multiple types of events to be on the same stream, but > > not for them to have just what each need, its a limitation, one that we > > can solve. I see no reason not to solve it :-) > > > > The evsel/evlist classes were designed to abstract away such details, > > i.e. perf_evlist__mmap should notice different sample_types and sort > > this out transparently. > > > > And then perf_evlist__mmap_read(evlist, idx), evlist->nr_mmaps should be > > enough to process the events :-) > > > > - Arnaldo > > An ABI change fixes the root cause of the current problem -- put an id > in perf_event_header. The id maps to the evsel which has the > sample_type. Right now you have to parse the sample to get the id to get > the evsel. This id is not always needed, so it shouldn't go to perf_event_header. Peter, can you comment here? ;-) - Arnaldo