Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268762AbUJEFFi (ORCPT ); Tue, 5 Oct 2004 01:05:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268776AbUJEFFi (ORCPT ); Tue, 5 Oct 2004 01:05:38 -0400 Received: from gizmo09ps.bigpond.com ([144.140.71.19]:28604 "HELO gizmo09ps.bigpond.com") by vger.kernel.org with SMTP id S268762AbUJEFFg (ORCPT ); Tue, 5 Oct 2004 01:05:36 -0400 Message-ID: <41622B9D.904@bigpond.net.au> Date: Tue, 05 Oct 2004 15:05:33 +1000 From: Peter Williams User-Agent: Mozilla Thunderbird 0.8 (X11/20040913) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Kenneth W Chen CC: Con Kolivas , Kenneth W , linux-kernel@vger.kernel.org Subject: Re: bug in sched.c:activate_task() References: <200410050216.i952Gb620657@unix-os.sc.intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1192 Lines: 31 Con Kolivas wrote: > Chen, Kenneth W writes: > >> Update p->timestamp to "now" in activate_task() doesn't look right >> to me at all. p->timestamp records last time it was running on a >> cpu. activate_task shouldn't update that variable when it queues >> a task on the runqueue. >> >> This bug (and combined with others) triggers improper load balancing. > > > The updated timestamp was placed there by Ingo to detect on-runqueue > time. If it is being used for load balancing then it is being used in > error. The ZAPHOD scheduler (being trialled in 2.6.9-rc3-mm2) uses its own time stamp so as not to interfere with the use of timestamp by load balancing code so it should be OK to delete this line form activate_task() in 2.6.9-rc3-mm2 without effecting ZAPHOD. Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce - 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/