Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754058Ab3EHLRa (ORCPT ); Wed, 8 May 2013 07:17:30 -0400 Received: from merlin.infradead.org ([205.233.59.134]:59085 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774Ab3EHLR3 (ORCPT ); Wed, 8 May 2013 07:17:29 -0400 Date: Wed, 8 May 2013 13:15:16 +0200 From: Peter Zijlstra To: Alex Shi Cc: Paul Turner , Ingo Molnar , Thomas Gleixner , Andrew Morton , Borislav Petkov , Namhyung Kim , Mike Galbraith , Morten Rasmussen , Vincent Guittot , Preeti U Murthy , Viresh Kumar , LKML , Mel Gorman , Rik van Riel , Michael Wang Subject: Re: [PATCH v5 3/7] sched: set initial value of runnable avg for new forked task Message-ID: <20130508111516.GA6803@dyad.programming.kicks-ass.net> References: <1367804711-30308-1-git-send-email-alex.shi@intel.com> <1367804711-30308-4-git-send-email-alex.shi@intel.com> <5187760D.8060900@intel.com> <51886460.3020009@intel.com> <51887404.4060102@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51887404.4060102@intel.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 820 Lines: 18 On Tue, May 07, 2013 at 11:24:52AM +0800, Alex Shi wrote: > It will give new forked task 1 ms extra running time. That will bring > incorrect info if the new forked goes to sleep a while. > But this info should benefit to some benchmarks like aim7, > pthread_cond_broadcast. So I am convinced. :) > > What's your opinion of this, Peter? We're going to get it wrong anyhow (lack of crystal ball instruction); overestimating the load seems like the best deal wrt latency for new tasks. The only other option we could try (not sure its even worth trying) would be half load. -- 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/