Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932137Ab2FDNTW (ORCPT ); Mon, 4 Jun 2012 09:19:22 -0400 Received: from relay.parallels.com ([195.214.232.42]:51159 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760416Ab2FDNTU convert rfc822-to-8bit (ORCPT ); Mon, 4 Jun 2012 09:19:20 -0400 From: Vladimir Davydov To: Arjan van de Ven CC: Ingo Molnar , Peter Zijlstra , Len Brown , Andrew Morton , "linux-kernel@vger.kernel.org" Date: Mon, 4 Jun 2012 17:19:08 +0400 Subject: Re: [PATCH] cpuidle: menu: use nr_running instead of cpuload for calculating perf mult Thread-Topic: [PATCH] cpuidle: menu: use nr_running instead of cpuload for calculating perf mult Thread-Index: Ac1CVKItH9QK1QugQ3KhVd3IYUN4vQ== Message-ID: <9511B40F-7F71-4A99-87B8-4CD88C83FE4E@parallels.com> References: <1338805485-10874-1-git-send-email-vdavydov@parallels.com> <4FCCB4DD.4060407@linux.intel.com> In-Reply-To: <4FCCB4DD.4060407@linux.intel.com> Accept-Language: en-US, ru-RU Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US, ru-RU Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1019 Lines: 21 On Jun 4, 2012, at 5:15 PM, "Arjan van de Ven" wrote: > 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. > > I use not the instantaneous nr_running, but nr_running last seen in update_cpu_load() where cpuload[0], which is currently used by cpuidle, is updated. -- 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/