From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965215AbWFIGGS (ORCPT ); Fri, 9 Jun 2006 02:06:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965224AbWFIGGS (ORCPT ); Fri, 9 Jun 2006 02:06:18 -0400 Received: from alt.aurema.com ([203.217.18.57]:16791 "EHLO smtp.sw.oz.au") by vger.kernel.org with ESMTP id S965215AbWFIGGR (ORCPT ); Fri, 9 Jun 2006 02:06:17 -0400 Message-ID: <44890F94.3050209@aurema.com> Date: Fri, 09 Jun 2006 16:05:08 +1000 From: Peter Williams Organization: Aurema Pty Ltd User-Agent: Thunderbird 1.5.0.2 (X11/20060501) MIME-Version: 1.0 To: MAEDA Naoaki CC: Kirill Korotaev , Srivatsa , CKRM , Balbir Singh , Mike Galbraith , Peter Williams , Con Kolivas , Linux Kernel , Sam Vilain , "Eric W. Biederman" , Kingsley Cheung , Rene Herman , Ingo Molnar Subject: Re: [ckrm-tech] [RFC 0/4] sched: Add CPU rate caps (improved) References: <20060606023708.2801.24804.sendpatchset@heathwren.pw.nest> <448688B2.2030206@jp.fujitsu.com> <4487D6B0.3080502@bigpond.net.au> <4488C765.2050108@aurema.com> <44890C0A.1000005@jp.fujitsu.com> In-Reply-To: <44890C0A.1000005@jp.fujitsu.com> 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 MAEDA Naoaki wrote: > Peter Williams wrote: >> I've done some informal testing with smaller values of CAP_STATS_OFFSET >> and there is only a minor improvement. >> >> However, something that does improve behaviour for short lived tasks is >> to increase the value of HZ. This is because the basic unit of CPU >> allocation by the scheduler is 1/HZ and this is also the minimum time >> (and granularity) with which sinbinning and other capping measures can >> be implemented. This is the fundamental limiting factor for the >> accuracy of capping i.e. if everything worked perfectly the best >> granularity that can be expected from capping of short lived tasks is >> 1000 / (HZ * duration) where duration is in seconds. > > I already defines CONFIG_HZ=1000. Do you suggest increasing more? No. Peter -- Dr Peter Williams, Chief Scientist Aurema Pty Limited Level 2, 130 Elizabeth St, Sydney, NSW 2000, Australia Tel:+61 2 9698 2322 Fax:+61 2 9699 9174 http://www.aurema.com