Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760557Ab2FDNPN (ORCPT ); Mon, 4 Jun 2012 09:15:13 -0400 Received: from mga01.intel.com ([192.55.52.88]:17724 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751670Ab2FDNPL (ORCPT ); Mon, 4 Jun 2012 09:15:11 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="160344851" Message-ID: <4FCCB4DD.4060407@linux.intel.com> Date: Mon, 04 Jun 2012 06:15:09 -0700 From: Arjan van de Ven User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Vladimir Davydov CC: Ingo Molnar , Peter Zijlstra , Len Brown , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] cpuidle: menu: use nr_running instead of cpuload for calculating perf mult References: <1338805485-10874-1-git-send-email-vdavydov@parallels.com> In-Reply-To: <1338805485-10874-1-git-send-email-vdavydov@parallels.com> X-Enigmail-Version: 1.4.1 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 Content-Length: 768 Lines: 16 On 6/4/2012 3:24 AM, Vladimir Davydov wrote: > rq->cpuload strongly depends on cgroup hierarchy. For example, if hundreds of > tasks are running inside cpu:/test cgroup, the sum of cpuload over all cpus > won't exceed 1024 (by default). That makes the cpuidle menu governor take wrong > decisions, which can negatively affect overall performance. nr_running is the wrong answer... it is instantaneous, not longer term. cpuidle wants a longer term, per cpu, notion of "busy", to use as proxy for performance sensitivity. -- 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/