From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030360AbWD1K1D (ORCPT ); Fri, 28 Apr 2006 06:27:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030364AbWD1K1D (ORCPT ); Fri, 28 Apr 2006 06:27:03 -0400 Received: from mail16.syd.optusnet.com.au ([211.29.132.197]:18108 "EHLO mail16.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S1030360AbWD1K1C (ORCPT ); Fri, 28 Apr 2006 06:27:02 -0400 From: Con Kolivas To: Mike Galbraith Subject: Re: [ckrm-tech] Re: [PATCH 0/9] CPU controller Date: Fri, 28 Apr 2006 20:26:38 +1000 User-Agent: KMail/1.9.1 Cc: linux-kernel@vger.kernel.org, Kirill Korotaev , MAEDA Naoaki , akpm@osdl.org, ckrm-tech@lists.sourceforge.net References: <20060428013730.9582.9351.sendpatchset@moscone.dvs.cs.fujitsu.co.jp> <200604282009.41725.kernel@kolivas.org> <1146219372.8067.31.camel@homer> In-Reply-To: <1146219372.8067.31.camel@homer> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200604282026.39520.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 28 April 2006 20:16, Mike Galbraith wrote: > On Fri, 2006-04-28 at 20:09 +1000, Con Kolivas wrote: > > On Friday 28 April 2006 17:46, Mike Galbraith wrote: > > > On Fri, 2006-04-28 at 09:11 +0200, Mike Galbraith wrote: > > > > On Fri, 2006-04-28 at 09:56 +0400, Kirill Korotaev wrote: > > > > > I'm also pretty sure, that CPU controller based on timeslice tricks > > > > > behaves poorly on burstable load patterns as well and with > > > > > interactive tasks. So before commiting I propose to perform a good > > > > > testing on different load patterns. > > > > > > > > Yes, it can only react very slowly. > > > > > > Actually, this might not be that much of a problem. I know I can > > > traverse queue heads periodically very cheaply. Traversing both active > > > and expired arrays to requeue starving tasks once every 100ms costs max > > > 4usecs (3GHz P4) for a typical distribution. > > > > How many tasks? Your function was O(n) so the more tasks the longer that > > max value was. > > Nope. It's not O(tasks), it's O(occupied_queues). Occupied queues is > generally not a large number. Ok well that P4 does about 700,000 context switches per second so 4us sounds large to me. -- -ck