From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757098Ab0ICU2u (ORCPT ); Fri, 3 Sep 2010 16:28:50 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:35933 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752829Ab0ICU2t (ORCPT ); Fri, 3 Sep 2010 16:28:49 -0400 Date: Fri, 3 Sep 2010 22:28:39 +0200 From: Ingo Molnar To: Thomas Renninger Cc: Jean Pihet , Peter Zijlstra , Len Brown , Arjan Van De Ven , arjan@infradead.org, Kevin Hilman , linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing, perf: add more power related events Message-ID: <20100903202839.GA8679@elte.hu> References: <201009032005.08268.trenn@suse.de> <20100903195555.GA1663@elte.hu> <201009032210.08524.trenn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201009032210.08524.trenn@suse.de> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -0.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-0.9 required=5.9 tests=BAYES_00,URIBL_RHS_DOB autolearn=no SpamAssassin version=3.2.5 1.1 URIBL_RHS_DOB Contains an URI of a new domain (Day Old Bread) [URIs: marc.info] -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Thomas Renninger wrote: > On Friday 03 September 2010 21:55:55 Ingo Molnar wrote: > > > > * Thomas Renninger wrote: > > > > > Hi Jean, > > > > > > Summary at the beginning if people stop reading on the details > > > below...: > > > Nice work! > > > You have my vote to get this merged. > > > I think it's up to Ingo to push it. > > > > Well, the patch that got posted: > > > > [PATCH] tracing, perf: add more power related events > > > > Only adds tracepoints to power.h, but doesnt actually use them anywhere > > ... > > > > Is there a companion patch i missed? > Yep. > Jean has nicely made up a tiny website he refered to in his mail: > http://www.omappedia.com/wiki/Power_Management_Debug_and_Profiling Ah, that wasnt in the first patch. (Please re-start discussion threads when something is re-submitted) Nice website. Looks like these new tracepoints are really useful. > There he shows the whole big patch and states: Generally it's nice to post patches to lkml too, so that people have something to discuss. > Since the patch touches generic files (in include/trace/events/power.h), it is split in parts: > * generic code: submitted to the LKML, cf. http://marc.info/?l=linux-kernel&m=128195697205096&w=4 , > * ARM/OMAP specific code for the already existing events: to be submitted to l-o, cf. http://www.spinics.net/lists/linux-omap/msg35357.html, > * ARM/OMAP specific code for the new events, to be submitted once the generic code is accepted. > > > Also, it would be nice to add it to x86 and to OMAP at once, and > > synchronize up all the power events > > I can add sleep state events to x86 acpi parts, but even these are, as > said, not that interesting as they might be on ARM ultra mobile use > cases. Yeah - but as long as they are at least attempted to be cross-platform, that would be fine. The ACPI folks are Cc:-ed so they can object if they dont like something. > > - and check how existing tools like > > powertop make use of such events - and sync it all up. > > Does powertop use these events? It certainly does quite a few things wrt. power usage analysis. Arjan is on the Cc:, maybe he has an opinion about these tracepoints. > > We dont want to have inconsistent, architecture-dependent events in > > the end, for obvious reasons. > > Jean also shows screenshots at the link above > how perf timechart or the the corresponding > gui app PyTimechart still works together with these. > I can't see how the new events should break an existing app, they should > just ignore events they are not aware of. Yeah, extensions rarely break anything. What i mentioned was 'inconsistent, architecture-dependent events', which is not a fact but a possible danger: as these new events are only for OMAP right now. They might be OK, they might be not OK - i dont know, that's why i suggested to make them cross-platform in practice too. So it would be nice to get some feedback from the ACPI folks - but if you guys can also do an ACPI patch that would be even better! Thanks, Ingo