From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932363Ab3GBHD7 (ORCPT ); Tue, 2 Jul 2013 03:03:59 -0400 Received: from mga14.intel.com ([143.182.124.37]:64908 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932219Ab3GBHDx (ORCPT ); Tue, 2 Jul 2013 03:03:53 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,979,1363158000"; d="scan'208";a="262946311" Message-ID: <51D27CC6.1050209@intel.com> Date: Tue, 02 Jul 2013 10:09:58 +0300 From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: David Ahern CC: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Frederic Weisbecker , Jiri Olsa , Mike Galbraith , Namhyung Kim , Paul Mackerras , Peter Zijlstra , Stephane Eranian Subject: Re: [PATCH V2 12/15] perf tools: allow non-matching sample types References: <1372319707-13892-1-git-send-email-adrian.hunter@intel.com> <1372319707-13892-13-git-send-email-adrian.hunter@intel.com> <51CC6AAF.4030404@gmail.com> <51D14CB6.206@intel.com> <51D1D043.5030509@gmail.com> In-Reply-To: <51D1D043.5030509@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/07/13 21:53, David Ahern wrote: > On 7/1/13 3:32 AM, Adrian Hunter wrote: >> Snip >> >>> >>> While this works for a combined S/W and tracepoint events session, I do not >>> like promoting sample types to the minimum compatible level for all events >>> in the session. perf needs to allow each event to have its own sample_type >>> and not force a minimal compatibility. >> >> Why? The impact is small. The kernel API is completely unchanged. > > I'd like to see libperf become a stable, usable library - usable by more > than the perf binary and its builtin commands. I have already done this once > for a daemon, and it was a PITA to get the specific use functional without > memory leaks/growth in the libperf part. > > With respect to this specific patch it means appropriate flexibility in the > data collected for events. ie., each event can have its own sample_type. For > example if the tracepoint already contains task information TID is not > needed - and IP may not be wanted either. The code processing the samples > should not require all events to have some minimum data format - that just > wastes buffer space. It would be more compelling to provide a use-case where that "waste" actually makes any difference.