Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752987Ab2HOW6b (ORCPT ); Wed, 15 Aug 2012 18:58:31 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:39750 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751765Ab2HOW63 (ORCPT ); Wed, 15 Aug 2012 18:58:29 -0400 MIME-Version: 1.0 In-Reply-To: <1345042516.31459.99.camel@twins> References: <5028F12C.7080405@intel.com> <1345042516.31459.99.camel@twins> Date: Thu, 16 Aug 2012 04:58:29 +0600 Message-ID: Subject: Re: [discussion]sched: a rough proposal to enable power saving in scheduler From: Rakib Mullick To: Peter Zijlstra Cc: Alex Shi , Suresh Siddha , Arjan van de Ven , vincent.guittot@linaro.org, svaidy@linux.vnet.ibm.com, Ingo Molnar , Andrew Morton , Linus Torvalds , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1511 Lines: 36 On Wed, Aug 15, 2012 at 8:55 PM, Peter Zijlstra wrote: > On Wed, 2012-08-15 at 20:24 +0600, Rakib Mullick wrote: >> How do you plan to test this power saving scheme? Using powertop? Or, >> is there any other tools? > > We should start out simple enough that we can validate it by looking at > task placement by hand, eg. 4 tasks on a dual socket quad-core, should > only keep one socket awake. > Yeah, that's what we can do "task placement", that's what scheduler is known for :). > We can also add an power aware evaluator to Linsched (another one of > those things that needs getting sorted). > > And yeah, someone running with a power meter is of course king. > > _BUT_ we shouldn't go off the wall with power meters as that very > quickly gets very specific to the system being measured. > > We should really keep this thing as simple as possible while still > providing some benefit for all various architectures without tons of per > arch knobs and knowhow. Perhaps this is because, there's no well sorted specification from various arch, to properly deal with power saving from scheduler's POV. Actually, this is what I wasn't really sure whether there's any documentation of how scheduler should work to save power. Thanks, Rakib -- 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/