From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e1.ny.us.ibm.com (e1.ny.us.ibm.com [32.97.182.141]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e1.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 24812B6F84 for ; Wed, 22 Jun 2011 02:30:49 +1000 (EST) Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by e1.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p5LGIsr5019904 for ; Tue, 21 Jun 2011 12:18:54 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p5LGUXct602192 for ; Tue, 21 Jun 2011 12:30:33 -0400 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p5LATgce003060 for ; Tue, 21 Jun 2011 04:29:44 -0600 Message-ID: <4E00C6DE.1030001@linux.vnet.ibm.com> Date: Tue, 21 Jun 2011 21:59:18 +0530 From: deepthi MIME-Version: 1.0 To: Benjamin Herrenschmidt Subject: Re: [PATCH] perf_events: Enable idle state tracing for pseries (ppc64) References: <20110601123554.GA12492@deepthi.in.ibm.com> <1308284659.32158.4.camel@pasglop> <4DFF80FD.8080600@linux.vnet.ibm.com> <1308606133.32158.143.camel@pasglop> In-Reply-To: <1308606133.32158.143.camel@pasglop> Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tuesday 21 June 2011 03:12 AM, Benjamin Herrenschmidt wrote: > On Mon, 2011-06-20 at 22:48 +0530, deepthi wrote: >> On Friday 17 June 2011 09:54 AM, Benjamin Herrenschmidt wrote: >>> On Wed, 2011-06-01 at 18:05 +0530, Deepthi Dharwar wrote: >>>> Hi, >>>> >>>> Please find below a patch, which has perf_events added for pseries (ppc64) >>>> platform in order to emit the trace required for perf timechart. >>>> It essentially enables perf timechart for pseries platfrom to analyse >>>> power savings events like cpuidle states. >>> >>> Unless I'm mistaken, you added traces to dedicated CPU idle sleep but >>> not shared processor. Any reason ? >>> >> Yes, the traces were added only to dedicated CPU idle sleep and not for >> shared processor. This was added only for RFC purpose, and looking for >> comments from trace implementation point of view. This can be >> easily extended to the latter too. > > Please do both. > Yes, I ll do so. >>> Also I don't really know that tracing stuff but what's the point of >>> having start/end _and trace_cpu_idle if you're going to always start & >>> end around a single occurence of trace_cpu_idle ? >>> >> power_start/end are the APIs that were used initially >> and they are going to be deprecated in the upcoming kernel releases. >> trace_cpu_idle call is going to replace power start/end routines. >> To maintain backward compatibility and uniformity, both the routines >> have been used. >> (ref:https://lkml.org/lkml/2010/11/14/60ref:https://lkml.org/lkml/2010/11/14/60) > > Backward compatible with what ? Userspace ? Do we care in that specific > case since it's a new feature ? > Going forward, we can just have trace_cpu_idle call and remove the power_start/end calls. >>> Wouldn't there be a way to start/end and then trace the snooze and >>> subsequent cede within the same start/end section or that makes no >>> sense ? >>> >> We wanted to find the residency time of both Snooze as well as cede >> separately. Knowing this will help us tweak our cpuidle code. So, both >> have been captured separately. >> >>> Also would there be any interest in doing the tracing more generically >>> in idle.c ? >>> >> Yes, this tracing is already implemented for Intel platform. This would >> be a part of cpuidle framework. Going further, once the power cpuidle >> framework is ported and ready, we will extend this trace there as well. >> (ref:https://lkml.org/lkml/2011/6/7/375) > > So do we need to apply this patch at all since the cpuidle stuff is > happening too ? > Well, not really. This is more for RFC purpose. I just wanted to share this patch, as we are using it to evaluate cpu idle on ppc64. > Cheers, > Ben. > > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev