Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932733Ab3CZNAx (ORCPT ); Tue, 26 Mar 2013 09:00:53 -0400 Received: from mail-bk0-f54.google.com ([209.85.214.54]:53923 "EHLO mail-bk0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757712Ab3CZNAw (ORCPT ); Tue, 26 Mar 2013 09:00:52 -0400 MIME-Version: 1.0 In-Reply-To: <1364301443.5053.9.camel@laptop> References: <1363955155-18382-1-git-send-email-vincent.guittot@linaro.org> <1363955155-18382-4-git-send-email-vincent.guittot@linaro.org> <1364301443.5053.9.camel@laptop> Date: Tue, 26 Mar 2013 14:00:50 +0100 Message-ID: Subject: Re: [RFC PATCH v3 3/6] sched: pack small tasks From: Vincent Guittot To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, mingo@kernel.org, linux@arm.linux.org.uk, pjt@google.com, santosh.shilimkar@ti.com, morten.rasmussen@arm.com, chander.kashyap@linaro.org, cmetcalf@tilera.com, tony.luck@intel.com, alex.shi@intel.com, preeti@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, tglx@linutronix.de, len.brown@intel.com, arjan@linux.intel.com, amit.kucheria@linaro.org, corbet@lwn.net 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: 1180 Lines: 30 On 26 March 2013 13:37, Peter Zijlstra wrote: > On Fri, 2013-03-22 at 13:25 +0100, Vincent Guittot wrote: >> +static bool is_light_task(struct task_struct *p) >> +{ >> + /* A light task runs less than 20% in average */ >> + return ((p->se.avg.runnable_avg_sum * 5) < >> + (p->se.avg.runnable_avg_period)); >> +} > > OK, so we have a 'problem' here, we initialize runnable_avg_* to 0, but > we want to 'assume' a fresh task is fully 'loaded'. IIRC Alex ran into > this as well. Hi Peter, The packing small tasks is only applied at wake up and not during fork or exec so the runnable_avg_* should have been initialized. As you mentionned, we assume that a fresh task is fully loaded and let the default scheduler behavior to select a target CPU Vincent > > PJT, do you have any sane solution for this, I forgot what the result > of the last discussion was -- was there any? > -- 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/