From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030856AbXCNN6r (ORCPT ); Wed, 14 Mar 2007 09:58:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030859AbXCNN6r (ORCPT ); Wed, 14 Mar 2007 09:58:47 -0400 Received: from caffeine.uwaterloo.ca ([129.97.134.17]:59857 "EHLO caffeine.csclub.uwaterloo.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030856AbXCNN6q (ORCPT ); Wed, 14 Mar 2007 09:58:46 -0400 Date: Wed, 14 Mar 2007 09:58:45 -0400 To: Jeremy Fitzhardinge Cc: Dan Hecht , dwalker@mvista.com, cpufreq@lists.linux.org.uk, Linux Kernel Mailing List , Con Kolivas , Chris Wright , Virtualization Mailing List , john stultz , Ingo Molnar , Thomas Gleixner Subject: Re: Stolen and degraded time and schedulers Message-ID: <20070314135845.GG22466@csclub.uwaterloo.ca> References: <45F6D1D0.6080905@goop.org> <1173816769.22180.14.camel@localhost> <45F70A71.9090205@goop.org> <1173821224.1416.24.camel@dwalker1> <45F71EA5.2090203@goop.org> <45F74515.7010808@vmware.com> <45F77C27.8090604@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45F77C27.8090604@goop.org> User-Agent: Mutt/1.5.9i From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 13, 2007 at 09:37:59PM -0700, Jeremy Fitzhardinge wrote: > (By monotonic time, I presume you mean monotonic real time.) Yes, I > suppose you could, but I don't think that's terribly useful. I think > work_time is probably most naturally measured in cpu clock cycles rather > than an actual time unit. You could convert it to ns, but I don't see > the point. > > I know its a term in general use, but I don't think the term "stolen > time" is all that useful, particularly when we're talking about a more > general notion of cpu work contributing to the progress of process > execution. In the cpufreq case, time isn't "stolen" per se. How would you deal with something like a pentium 4 HT processor where you may run slower just because you got scheduled on the sibling of a cpu that happens to run something else needing the same execution units you do, causing you to get delayed more, even though the cpu is running full speed and nothing else is trying to use your "cpu"? I don't think there is any way to know what the real impact of two processes on a HT cpu have on each other. Interesting goal. Not sure it can be done. -- Len Sorensen