From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030866AbXCNTxd (ORCPT ); Wed, 14 Mar 2007 15:53:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030872AbXCNTxd (ORCPT ); Wed, 14 Mar 2007 15:53:33 -0400 Received: from mx1.redhat.com ([66.187.233.31]:56238 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030866AbXCNTxc (ORCPT ); Wed, 14 Mar 2007 15:53:32 -0400 Message-ID: <45F850BF.5030702@redhat.com> Date: Wed, 14 Mar 2007 15:45:03 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 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 , paulus@au.ibm.com, schwidefsky@de.ibm.com Subject: Re: Stolen and degraded time and schedulers 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> <45F846AB.6060200@vmware.com> <45F84E39.7030507@goop.org> In-Reply-To: <45F84E39.7030507@goop.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: >> How is time quantum getting stolen less important? Time quantum >> getting stolen results directly in more unnecessary context switches >> since we might steal the entire timeslice before the process even ran. > > It doesn't matter why you didn't get the time; Oh, but it does. System administrators can use steal time the same way they use iowait time: to spot bottlenecks on their systems. If you have a lot of iowait time, you know you want either faster IO or more memory. If you have a lot of steal time, you know you need to spread your virtual machines over more CPUs. Steal time allows you to see the difference between a busy system and an overloaded system. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic.