Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753703Ab2FDRSL (ORCPT ); Mon, 4 Jun 2012 13:18:11 -0400 Received: from merlin.infradead.org ([205.233.59.134]:35958 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414Ab2FDRSK convert rfc822-to-8bit (ORCPT ); Mon, 4 Jun 2012 13:18:10 -0400 Message-ID: <1338830279.28282.117.camel@twins> Subject: Re: [PATCH] cpuidle: menu: use nr_running instead of cpuload for calculating perf mult From: Peter Zijlstra To: Vladimir Davydov Cc: Arjan van de Ven , Ingo Molnar , Len Brown , Andrew Morton , "linux-kernel@vger.kernel.org" Date: Mon, 04 Jun 2012 19:17:59 +0200 In-Reply-To: <33E662E8-48BF-49A7-A4A0-CB1A751AAEBC@parallels.com> References: <1338805485-10874-1-git-send-email-vdavydov@parallels.com> <1338805967.28282.12.camel@twins> <4FCCB486.4040905@linux.intel.com> <1338817519.28282.54.camel@twins> <4FCCBC97.8060101@linux.intel.com> <1338822509.28282.65.camel@twins> <4FCCD0CD.8080700@linux.intel.com> <1338823568.28282.79.camel@twins> <4FCCD6B7.4030703@linux.intel.com> <1338827607.28282.99.camel@twins> <4FCCE823.8090700@linux.intel.com> <33E662E8-48BF-49A7-A4A0-CB1A751AAEBC@parallels.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 967 Lines: 19 On Mon, 2012-06-04 at 21:08 +0400, Vladimir Davydov wrote: > But this_cpu_load(), which is currently used by cpuidle, does not > return the "load average". It returns the value of cpuload at some > moment in the past (actually, the value is updated in > update_cpu_load()). This value is usually used for load balancing. > > Moreover, this value does not reflect the real cpu load from the > cpuidle pow, because it depends on tasks priority (nice) and, what is > worse, with the introduction of cgroups it can be pretty arbitrary. > For instance, each group of tasks is accounted just as a single task > with standard priority "spreaded" among all cpus, no matter how many > tasks are actually running in it. Indeed. -- 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/