From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756728AbZLWSHX (ORCPT ); Wed, 23 Dec 2009 13:07:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754651AbZLWSHW (ORCPT ); Wed, 23 Dec 2009 13:07:22 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:34402 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751989AbZLWSHW (ORCPT ); Wed, 23 Dec 2009 13:07:22 -0500 Subject: Re: SCHED: Is task migration necessary in sched_exec(). From: Peter Zijlstra To: Rakib Mullick Cc: Ingo Molnar , LKML In-Reply-To: References: <1261563687.4937.120.camel@laptop> <1261565584.4937.124.camel@laptop> <1261569112.4937.135.camel@laptop> <1261570834.4937.141.camel@laptop> Content-Type: text/plain; charset="UTF-8" Date: Wed, 23 Dec 2009 19:06:43 +0100 Message-ID: <1261591603.4937.153.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2009-12-23 at 18:52 +0600, Rakib Mullick wrote: > Yes - a fair win. But if load balancer moves other tasks from the runqueue > (2nd or 3rd task from your ex.) and thats how we also can achive 1/2 of cpu1's > time , right? Those waiting tasks could have effective 0 cache footprint too. > If they were not run before - right? Could have, but is very unlikely, and here we have one we know for sure.