From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272367AbTHECL0 (ORCPT ); Mon, 4 Aug 2003 22:11:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272370AbTHECL0 (ORCPT ); Mon, 4 Aug 2003 22:11:26 -0400 Received: from dyn-ctb-210-9-244-254.webone.com.au ([210.9.244.254]:49927 "EHLO chimp.local.net") by vger.kernel.org with ESMTP id S272367AbTHECLV (ORCPT ); Mon, 4 Aug 2003 22:11:21 -0400 Message-ID: <3F2F1236.6050900@cyberone.com.au> Date: Tue, 05 Aug 2003 12:11:02 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3.1) Gecko/20030618 Debian/1.3.1-3 X-Accept-Language: en MIME-Version: 1.0 To: Con Kolivas CC: linux kernel mailing list , Andrew Morton , Ingo Molnar , Felipe Alfaro Solana Subject: Re: [PATCH] O13int for interactivity References: <200308050207.18096.kernel@kolivas.org> In-Reply-To: <200308050207.18096.kernel@kolivas.org> 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 Con Kolivas wrote: >Changes: > >Reverted the child penalty to 95 as new changes help this from hurting > >Changed the logic behind loss of interactive credits to those that burn off >all their sleep_avg > >Now all tasks get proportionately more sleep as their relative bonus drops >off. This has the effect of detecting a change from a cpu burner to an >interactive task more rapidly as in O10. > >The _major_ change in this patch is that tasks on uninterruptible sleep do not >earn any sleep avg during that sleep; it is not voluntary sleep so they should >not get it. This has the effect of stopping cpu hogs from gaining dynamic >priority during periods of heavy I/O. Very good for the jerks you may >see in X or audio skips when you start a whole swag of disk intensive cpu hogs >(eg make -j large number). I've simply dropped all their sleep_avg, but >weighting it may be more appropriate. This has the side effect that pure >disk tasks (eg cp) have relatively low priority which is why weighting may >be better. We shall see. > I don't think this is a good idea. Uninterruptible does not mean its not a voluntary sleep. Its more to do with how a syscall is implemented. I don't think it should be treated any differently to any other type of sleep. Any task which calls schedule in kernel context is sleeping volintarily - if implicity due to having called a blocking syscall. > >Please test this one extensively. It should _not_ affect I/O throughput per >se, but I'd like to see some of the I/O benchmarks on this. I do not want to >have detrimental effects elsewhere. > Well the reason it can affect IO thoughput is for example when there is an IO bound process and a CPU hog on the same processor: the longer the IO process has to wait (after being woken) before being run, the more chance the disk will fall idle for a longer period. And of course the CPU uncontended case is somewhat uninteresting when it comes to a CPU scheduler.