From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268933AbUHMBoL (ORCPT ); Thu, 12 Aug 2004 21:44:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268934AbUHMBoK (ORCPT ); Thu, 12 Aug 2004 21:44:10 -0400 Received: from gizmo03bw.bigpond.com ([144.140.70.13]:64668 "HELO gizmo03bw.bigpond.com") by vger.kernel.org with SMTP id S268933AbUHMBoE (ORCPT ); Thu, 12 Aug 2004 21:44:04 -0400 Message-ID: <411C1CE0.8040101@bigpond.net.au> Date: Fri, 13 Aug 2004 11:44:00 +1000 From: Peter Williams User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: spaminos-ker@yahoo.com CC: linux-kernel@vger.kernel.org, William Lee Irwin III Subject: Re: Scheduler fairness problem on 2.6 series (Attn: Nick Piggin and others) References: <20040813001304.59753.qmail@web13912.mail.yahoo.com> In-Reply-To: <20040813001304.59753.qmail@web13912.mail.yahoo.com> 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 spaminos-ker@yahoo.com wrote: > --- Peter Williams wrote: > >>I've just run your tests on my desktop and with max_ia_bonus at its >>default value I see the "delta = 3" with 20 threads BUT when I set >>max_ia_bonus to zero they stop (in both "eb" and "pb" mode). So I then >>reran the tests with 60 threads and zero max_ia_bonus and no output was >>generated by your testdelay script in either "eb" or "pb" modes. I >>didn't try "sc" mode as I have a ZAPHOD kernel loaded (not HYDRA) but >>Con has reported that the problem is absent in his latest patches so >>I'll update the "sc" mode in HYDRA to those patches. >> > > > I just tried the same test on spa-zaphod-linux 4.1 over 2.6.8-rc4 > > I also have messages with 20 threads "delta = 3" that go away when I set > max_ia_bonus to 0 (and stay off with 60 threads too) in "pb" mode. I'm going to do some experiments to measure the relationship between the size of max_ia_bonus and the observed delays to see if there's value that gives acceptable performance without turning bonuses off completely. > But, unlike your desktop, the "eb" mode doesn't seem to get better by setting > max_ia_bonus to 0 on my machine, maybe I need to tweak something else? (even > though, the idea of tweaking for a given workload doesn't sound very good to > me). You could try increasing "base_promotion_interval". When I have a better idea of the best values (for each mode) for the various parameters I'll reset their values when the mode is changed. > > The "pb" mode is very responsive with the system under heavy load, I like it :) That's good to hear. If you have time, I'd appreciate if you could try a few different values of max_ia_bonus to determine the minimum value that still gives good responsiveness for your system? I'm trying to get a feel for how much this varies from system to system. > > I will run some tests over the week end with the actual server to see the > effect of this patch on a more complex system. > > Nicolas > > PS: the machine I am using is a pure server, only accessible through ssh, so I > can not really tell the behavior under X. If it's a pure server I imagine that it's not running X. On a pure server I'd recommend setting max_ia_bonus to zero. Thanks Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce