Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760272Ab3CHChg (ORCPT ); Thu, 7 Mar 2013 21:37:36 -0500 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:53343 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760229Ab3CHChf (ORCPT ); Thu, 7 Mar 2013 21:37:35 -0500 Message-ID: <51394EE3.1020706@linux.vnet.ibm.com> Date: Fri, 08 Mar 2013 10:37:23 +0800 From: Michael Wang User-Agent: Mozilla/5.0 (X11; Linux i686; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Mike Galbraith CC: Peter Zijlstra , LKML , Ingo Molnar , Namhyung Kim , Alex Shi , Paul Turner , Andrew Morton , "Nikunj A. Dadhania" , Ram Pai Subject: Re: [PATCH] sched: wakeup buddy References: <5136EB06.2050905@linux.vnet.ibm.com> <1362645372.2606.11.camel@laptop> <1362649419.4652.12.camel@marge.simpson.net> In-Reply-To: <1362649419.4652.12.camel@marge.simpson.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13030802-2000-0000-0000-00000B390CF3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1757 Lines: 44 On 03/07/2013 05:43 PM, Mike Galbraith wrote: > On Thu, 2013-03-07 at 09:36 +0100, Peter Zijlstra wrote: >> On Wed, 2013-03-06 at 15:06 +0800, Michael Wang wrote: >> >>> wake_affine() stuff is trying to bind related tasks closely, but it doesn't >>> work well according to the test on 'perf bench sched pipe' (thanks to Peter). >> >> so sched-pipe is a poor benchmark for this.. >> >> Ideally we'd write a new benchmark that has some actual data footprint >> and we'd measure the cost of tasks being apart on the various cache >> metrics and see what affine wakeup does for it. >> >> Before doing something like what you're proposing, I'd have a hard look >> at WF_SYNC, it is possible we should disable/fix select_idle_sibling >> for sync wakeups. > > If nobody beats me to it, I'm going to try tracking shortest round trip > to idle, and use a multiple of that to shut select_idle_sibling() down. > If avg_idle approaches round trip time, there's no win to be had, we're > just wasting cycles. That's great if we have it, I'm a little doubt whether it is possible to find a better way to replace the select_idle_sibling() (look at the way it locates idle cpu...) in some cases, but I'm looking forward it ;-) Regards, Michael Wang > > -Mike > > -- > 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/ > -- 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/