From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934415Ab1JaL6W (ORCPT ); Mon, 31 Oct 2011 07:58:22 -0400 Received: from out3.smtp.messagingengine.com ([66.111.4.27]:49745 "EHLO out3.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932810Ab1JaL6V (ORCPT ); Mon, 31 Oct 2011 07:58:21 -0400 X-Sasl-enc: 9GCUrAEIbJJ/VcW+wlcPSrIdr3zRfJBZz/E2i3gCyQ6h 1320062300 Date: Mon, 31 Oct 2011 09:58:17 -0200 From: Henrique de Moraes Holschuh To: "Artem S. Tashkinov" Cc: linux-kernel@vger.kernel.org Subject: Re: HT (Hyper Threading) aware process scheduling doesn't work as it should Message-ID: <20111031115817.GA20448@khazad-dum.debian.net> References: <269467866.49093.1320004632156.JavaMail.mail@webmail17> <20111030212644.GA7106@khazad-dum.debian.net> <815860869.50724.1320011477430.JavaMail.mail@webmail17> <20111031091607.GB7106@khazad-dum.debian.net> <574299906.69412.1320054001912.JavaMail.mail@webmail05> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <574299906.69412.1320054001912.JavaMail.mail@webmail05> X-GPG-Fingerprint: 1024D/1CDB0FE3 5422 5C61 F6B7 06FB 7E04 3738 EE25 DE3F 1CDB 0FE3 User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 31 Oct 2011, Artem S. Tashkinov wrote: > > On Oct 31, 2011, Henrique de Moraes Holschuh wrote: > > > > On Sun, 30 Oct 2011, Artem S. Tashkinov wrote: > > > > Please make sure both are set to 0. If they were not 0 at the time you > > > > ran your tests, please retest and report back. > > > > > > That's 0 & 0 for me. > > > > How idle is your system during the test? > > load average: 0.00, 0.00, 0.00 I believe cpuidle will interfere with the scheduling in that case. Could you run your test with higher loads (start with one, and go up to eight tasks that are CPU-hogs, measuring each step)? > I have to insist that people conduct this test on their own without trusting my > words. Probably there's something I overlook or don't fully understand but from What you should attempt to do is to give us a reproducible test case. A shell script or C/perl/python/whatever program that when run clearly shows the problem you're complaining about on your system. Failing that, a very detailed description (read: step by step) of how you're testing things. I can't see anything wrong in my X5550 workstation (4 cores, 8 threads, single processor, i.e. not NUMA) running 3.0.8. > what I see, there's a serious issue here (at least Microsoft XP and 7 work exactly So far it looks like that, since your system is almost entirely idle, it could be trying to minimize task-run latency by scheduling work to the few cores/threads that are not in deep sleep (they take time to wake up, are often cache-cold, etc). Please use tools/power/x86/turbostat to track core usage and idle-states instead of top/htop. That might give you better information, and I think you will appreciate getting to know that tool. Note: turbostat reports *averages* for each thread. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh