Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759352AbYLQIUe (ORCPT ); Wed, 17 Dec 2008 03:20:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751548AbYLQIUY (ORCPT ); Wed, 17 Dec 2008 03:20:24 -0500 Received: from smtp-out.google.com ([216.239.45.13]:30762 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751249AbYLQIUX (ORCPT ); Wed, 17 Dec 2008 03:20:23 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:content-transfer-encoding; b=RUbaGAkHvCOrHW4GQWgjS7XJQ384foAqhZRDhPkaZYhHZ2G26vJlZJAt9fYK1V4+x 8CSLVnHdbjS5cEiqtvg1g== MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 17 Dec 2008 00:20:19 -0800 Message-ID: Subject: Re: [patch] sched: fix uneven per-cpu task_group share distribution From: Ken Chen To: Ingo Molnar , Peter Zijlstra Cc: Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 15, 2008 at 11:37 PM, Ken Chen wrote: > While testing CFS scheduler on linux-2.6-tip tree > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip > > We found that task which is pinned to a CPU could be starved relative to its > allocated fair share. I just want to poke you two to see if you have time to look over this patch. There is a real bug in linux-2.6-tip tree. If I create a CFS cgroup under directory .../parent/cgdir, put one task under 'parent' with CFS weight 1024, and one task under 'cgdir' (cgdir has group weight of 1024 also), pin both tasks onto same CPU. The CPU cycle allocation on these two tasks will be N:1 where N is number of CPUs in the system. The expected allocation should be 1:1. - Ken -- 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/