Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752826AbaAWMcx (ORCPT ); Thu, 23 Jan 2014 07:32:53 -0500 Received: from fw-tnat.austin.arm.com ([217.140.110.23]:17995 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751681AbaAWMcv (ORCPT ); Thu, 23 Jan 2014 07:32:51 -0500 Date: Thu, 23 Jan 2014 12:32:52 +0000 From: Morten Rasmussen To: Alex Shi Cc: Peter Zijlstra , Jason Low , Ingo Molnar , "vincent.guittot@linaro.org" , "daniel.lezcano@linaro.org" , Mike Galbraith , "wangyun@linux.vnet.ibm.com" , Linux Kernel Mailing List Subject: Re: [PATCH 2/2] sched: add statistic for rq->max_idle_balance_cost Message-ID: <20140123123252.GC19029@e103034-lin> References: <1390282399-17091-1-git-send-email-alex.shi@linaro.org> <1390282399-17091-2-git-send-email-alex.shi@linaro.org> <52DF802D.4030608@linaro.org> <20140122160901.GW13532@twins.programming.kicks-ass.net> <1390414208.2866.11.camel@j-VirtualBox> <52E0BB75.2080102@linaro.org> <20140123095443.GQ30183@twins.programming.kicks-ass.net> <52E0F3BF.5020904@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52E0F3BF.5020904@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 23, 2014 at 10:49:35AM +0000, Alex Shi wrote: > On 01/23/2014 05:54 PM, Peter Zijlstra wrote: > > On Thu, Jan 23, 2014 at 02:49:25PM +0800, Alex Shi wrote: > >> On 01/23/2014 02:10 AM, Jason Low wrote: > >>>>>>> P64(avg_idle); > >>>>>>> + P64(max_idle_balance_cost); > >>>>>>> #endif > >>>>>>> P(ttwu_count); > >>>>> > >>>>> Not also the per-sd value in sd_alloc_ctl_domain_table() ? > >>> Yeah, tracking the sd->max_newidle_lb_cost can also be useful. > >>> > >>> > >> > >> Thanks for suggestion! > >> > >> I thought the sd->max_newidle_lb_cost keep changing. But yes, it's > >> still meaningful. > >> BTW, in the pandaboard ES, sd balance cost is about 1~2ms. > > > > That's an insane amount of time for only 2 cpus. > > maybe, :( > > but it is the data. > $ cat /proc/sys/kernel/sched_domain/cpu0/domain0/max_newidle_lb_cost > 1873393 What sort of workload are you running? It seems rather extreme. I did a quick test on TC2 and got max_newidle_lb_cost in the range ~7000-80000 when having a constantly running task on each cpu for a few seconds. I also traced curr_cost just to get an idea of the cost of idle_balance. I get an average cost across all five cpus of around 7000. Morten -- 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/