From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752643AbaIJOXt (ORCPT ); Wed, 10 Sep 2014 10:23:49 -0400 Received: from mail-oi0-f54.google.com ([209.85.218.54]:65120 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752358AbaIJOUQ (ORCPT ); Wed, 10 Sep 2014 10:20:16 -0400 MIME-Version: 1.0 In-Reply-To: <20140910135339.GQ3190@worktop.ger.corp.intel.com> References: <1409051215-16788-1-git-send-email-vincent.guittot@linaro.org> <1409051215-16788-7-git-send-email-vincent.guittot@linaro.org> <20140910135339.GQ3190@worktop.ger.corp.intel.com> From: Vincent Guittot Date: Wed, 10 Sep 2014 16:19:56 +0200 Message-ID: Subject: Re: [PATCH v5 06/12] sched: add per rq cpu_capacity_orig To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel , Preeti U Murthy , Russell King - ARM Linux , LAK , Rik van Riel , Morten Rasmussen , Mike Galbraith , Nicolas Pitre , "linaro-kernel@lists.linaro.org" , Daniel Lezcano , Dietmar Eggemann 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 On 10 September 2014 15:53, Peter Zijlstra wrote: > On Tue, Aug 26, 2014 at 01:06:49PM +0200, Vincent Guittot wrote: >> This new field cpu_capacity_orig reflects the available capacity of a CPUs >> unlike the cpu_capacity which reflects the current capacity that can be altered >> by frequency and rt tasks. >> > > No real objection to the patch as such, but the Changelog fails to tell > us why you want this. the cpu_capacity_orig is used in several places in the following patches to detect when a CPU's capacity has been noticeably reduced so we can trig load balance to look for a CPU with full capacity. As an example, we can detect when a CPU handles a significant amount of irq (with CONFIG_IRQ_TIME_ACCOUNTING) but is seen as an idle CPU by scheduler whereas really idle CPU are available From mboxrd@z Thu Jan 1 00:00:00 1970 From: vincent.guittot@linaro.org (Vincent Guittot) Date: Wed, 10 Sep 2014 16:19:56 +0200 Subject: [PATCH v5 06/12] sched: add per rq cpu_capacity_orig In-Reply-To: <20140910135339.GQ3190@worktop.ger.corp.intel.com> References: <1409051215-16788-1-git-send-email-vincent.guittot@linaro.org> <1409051215-16788-7-git-send-email-vincent.guittot@linaro.org> <20140910135339.GQ3190@worktop.ger.corp.intel.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10 September 2014 15:53, Peter Zijlstra wrote: > On Tue, Aug 26, 2014 at 01:06:49PM +0200, Vincent Guittot wrote: >> This new field cpu_capacity_orig reflects the available capacity of a CPUs >> unlike the cpu_capacity which reflects the current capacity that can be altered >> by frequency and rt tasks. >> > > No real objection to the patch as such, but the Changelog fails to tell > us why you want this. the cpu_capacity_orig is used in several places in the following patches to detect when a CPU's capacity has been noticeably reduced so we can trig load balance to look for a CPU with full capacity. As an example, we can detect when a CPU handles a significant amount of irq (with CONFIG_IRQ_TIME_ACCOUNTING) but is seen as an idle CPU by scheduler whereas really idle CPU are available