From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.mail.elte.hu (mx2.mail.elte.hu [157.181.151.9]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 26206DDDFC for ; Mon, 28 Jan 2008 23:33:16 +1100 (EST) Date: Mon, 28 Jan 2008 13:32:53 +0100 From: Ingo Molnar To: Peter Zijlstra Subject: Re: ppc32: Weird process scheduling behaviour with 2.6.24-rc Message-ID: <20080128123253.GA32496@elte.hu> References: <1201092131.6341.51.camel@lappy> <1201244082.6815.128.camel@pasglop> <1201244618.6815.130.camel@pasglop> <1201245901.6815.133.camel@pasglop> <1201251000.6341.108.camel@lappy> <20080126040734.GA21365@linux.vnet.ibm.com> <1201320834.6815.160.camel@pasglop> <20080126050757.GB14177@linux.vnet.ibm.com> <1201450409.1931.23.camel@thor.sulgenrain.local> <1201510236.6149.24.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1201510236.6149.24.camel@lappy> Cc: linuxppc-dev@ozlabs.org, Michel =?iso-8859-1?Q?D=E4nzer?= , vatsa@linux.vnet.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , * Peter Zijlstra wrote: > > * With CONFIG_FAIR_USER_SCHED disabled, there are severe > > interactivity hickups with a niced CPU hog and top running. This > > started with commit 810e95ccd58d91369191aa4ecc9e6d4a10d8d0c8. > > The revert at the bottom causes the wakeup granularity to shrink for + > nice and to grow for - nice. That is, it becomes easier to preempt a + > nice task, and harder to preempt a - nice task. i think it would be OK to do half of this: make it easier to preempt a +nice task. Michel, do you really need the -nice portion as well? It's not a problem to super-preempt positively reniced tasks, but it can be quite annoying if negatively reniced tasks have super-slices. Ingo