From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754379AbZLWKqc (ORCPT ); Wed, 23 Dec 2009 05:46:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752348AbZLWKqc (ORCPT ); Wed, 23 Dec 2009 05:46:32 -0500 Received: from mail-pw0-f42.google.com ([209.85.160.42]:58068 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751046AbZLWKqb (ORCPT ); Wed, 23 Dec 2009 05:46:31 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=kewQQAjgVKjgCDKmdzaw2SFLGIecUg5+pl9LhUE80cALUgyO+v7SE9qI/VJ3n9hORY 0Yv9m4ZdqDWpN/4krvgYUYD5zMAcuAmr6KD5oHUuL8uQMP7qv+GrutTQQKmdEHBGAK8s rBtVXAwLBFzkR6WKG2eSNBiNtIvEWCDs5oK+g= MIME-Version: 1.0 In-Reply-To: <1261563687.4937.120.camel@laptop> References: <1261563687.4937.120.camel@laptop> Date: Wed, 23 Dec 2009 16:46:31 +0600 Message-ID: Subject: Re: SCHED: Is task migration necessary in sched_exec(). From: Rakib Mullick To: Peter Zijlstra Cc: Ingo Molnar , LKML 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 On 12/23/09, Peter Zijlstra wrote: > On Wed, 2009-12-23 at 16:14 +0600, Rakib Mullick wrote: > > > Well, if there's an imbalance the 'slow' load-balancer will move it > around eventually anyway, and since it will then have build up a larger > cache footprint it will be even more expensive. > If there is an imbalance - then the overloaded task will moved. Why the _current_ task? It is getting the CPU that it was waiting for. We need to move overloaded task, not a task which is about to get execute. At this perticular moment pushing it away doesn't make sense, isn't it? > So moving it when its cheapest is the best all-round trade-off, isn't > it? I don't have any argue with cache footprint issue. > > thanks,