From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759032AbYDAL43 (ORCPT ); Tue, 1 Apr 2008 07:56:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753775AbYDAL4V (ORCPT ); Tue, 1 Apr 2008 07:56:21 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:32845 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753498AbYDAL4V (ORCPT ); Tue, 1 Apr 2008 07:56:21 -0400 Subject: Re: [PATCH 1/2] Customize sched domain via cpuset From: Peter Zijlstra To: Andi Kleen Cc: Hidetoshi Seto , linux-kernel@vger.kernel.org, Ingo Molnar , Paul Jackson In-Reply-To: <87zlsdzttp.fsf@basil.nowhere.org> References: <47F21BE3.5030705@jp.fujitsu.com> <87zlsdzttp.fsf@basil.nowhere.org> Content-Type: text/plain Date: Tue, 01 Apr 2008 13:56:08 +0200 Message-Id: <1207050968.8514.721.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.21.92 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2008-04-01 at 13:40 +0200, Andi Kleen wrote: > Hidetoshi Seto writes: > > > Using cpuset, now we can partition the system into multiple sched domains. > > Then, how about providing different characteristics for each domains? > > Did you actually see much improvement in any relevant workload > from tweaking these parameters? If yes what did you change? > And how much did it gain? > > Ideally the kernel should perform well without much tweaking > out of the box, simply because most users won't tweak. Adding a > lot of such parameters would imply giving up on good defaults which > is not a good thing. >>From what I understand they need very aggressive idle balancing; much more so than what is normally healty. I can see how something like that can be useful when you have a lot of very short running tasks. These could pile up on a few cpus and leave others idle.