From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261931AbUEADlW (ORCPT ); Fri, 30 Apr 2004 23:41:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261925AbUEADlW (ORCPT ); Fri, 30 Apr 2004 23:41:22 -0400 Received: from smtp017.mail.yahoo.com ([216.136.174.114]:14988 "HELO smtp017.mail.yahoo.com") by vger.kernel.org with SMTP id S261786AbUEADlU (ORCPT ); Fri, 30 Apr 2004 23:41:20 -0400 Message-ID: <40931C56.4030500@yahoo.com.au> Date: Sat, 01 May 2004 13:41:10 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040401 Debian/1.6-4 X-Accept-Language: en MIME-Version: 1.0 To: FabF CC: Andrew Morton , linux-kernel@vger.kernel.org, Badari Pulavarty Subject: Re: [PATCH 2.6.6-rc3-mm1] Add maxthinktime to sysfs References: <1083364002.6303.9.camel@bluerhyme.real3> <20040430154246.2019f9ec.akpm@osdl.org> <1083368224.4976.9.camel@bluerhyme.real3> In-Reply-To: <1083368224.4976.9.camel@bluerhyme.real3> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org FabF wrote: > On Sat, 2004-05-01 at 00:42, Andrew Morton wrote: >>Badari, did you find any need to vary this in the AS tuning work which you >>were doing? (What happened to that, btw?) >> >>If we're going to expose this tunable to users it needs to be documented in >>as-iosched.txt > > > I'm an absolute beginner Andrew ... Maybe someone more experienced could do that ? > No no, writing end user documentation is much easier than writing kernel code! But either way you needn't worry about it because this isn't something that you would want to tweak from userspace really. If you find it useful to do some tuning then I guess it can go in -mm. > PS:Attached the patch v2. > > Best regards, > Fabian > > > ------------------------------------------------------------------------ > > ffbench 11 - Fabian Frederick 04/2004 - asio - maxthinktime - 10 clients > 5 100 300 > --------------------- > 5.37 21.26 16.28 > 11.71 23.10 20.14 > 15.22 21.05 20.20 > 13.85 18.03 17.55 > 11.58 16.39 16.86 ... maxthinktime of 5 is below the default antic_expire of 6. This basically turns off the thinktime heuristic, so it isn't really surprising that it runs like crap. The *minimum* maxthinktime you should be playing with is probably about double the antic_expire value. Raising the value will make the heuristic a bit more restrictive which could be a good idea. I think OSDL's STP has a couple of database tests where the anticipatory scheduler has a small regression (dbt2, dbt3). They might be helpful to you.