From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752978AbYIXPTr (ORCPT ); Wed, 24 Sep 2008 11:19:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751954AbYIXPTj (ORCPT ); Wed, 24 Sep 2008 11:19:39 -0400 Received: from zrtps0kn.nortel.com ([47.140.192.55]:55256 "EHLO zrtps0kn.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751550AbYIXPTj (ORCPT ); Wed, 24 Sep 2008 11:19:39 -0400 Message-ID: <48DA5A84.8030704@nortel.com> Date: Wed, 24 Sep 2008 09:19:32 -0600 From: "Chris Friesen" User-Agent: Thunderbird 2.0.0.16 (X11/20080707) MIME-Version: 1.0 To: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: unpredictability in scheduler test results -- still present References: <48D2DA0D.4060300@nortel.com> In-Reply-To: <48D2DA0D.4060300@nortel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 24 Sep 2008 15:19:33.0962 (UTC) FILETIME=[F3007AA0:01C91E58] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Chris Friesen wrote: > I'm using the test config listed at the bottom. It's pretty > straightforward. > On the second run, the task distribution is almost perfect, but the > system was only using one of the two cpus as seen by the difference > between actual and expected cpu time. > > Warning, actual cpu time different than expected. actual: 10033.011108, > expected: 20000.000000 > group actual(%) expected(%) avg latency(ms) max_latency(ms) > 1 0.24(30.59/29.88) 30.00 26/27 68/58 > 2 39.87 40.00 20 36 > 3 29.89(29.87/29.91) 30.00 28/27 47/60 This behaviour (that load balancing is messed up) is now almost continuous with both current tip/master and current Linus git. On the first test after booting, it seems to work okay (although there are still issues with fairness). On every subsequent test, fairness is good but it only uses one of the two cpus. Also, building a kernel with "-j10" results in one cpu being mostly idle while the other one is 100% busy. It used to be both 100% busy--if I get time today I may try bisecting it. Chris