From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id C4C19DDDFC for ; Fri, 25 Jan 2008 17:55:14 +1100 (EST) Subject: Re: ppc32: Weird process scheduling behaviour with 2.6.24-rc From: Benjamin Herrenschmidt To: Peter Zijlstra In-Reply-To: <1201092131.6341.51.camel@lappy> References: <1200659696.23161.81.camel@thor.sulgenrain.local> <1201013786.4726.28.camel@thor.sulgenrain.local> <1201090699.9052.39.camel@thor.sulgenrain.local> <1201092131.6341.51.camel@lappy> Content-Type: text/plain Date: Fri, 25 Jan 2008 17:54:42 +1100 Message-Id: <1201244082.6815.128.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Ingo Molnar , Michel =?ISO-8859-1?Q?D=E4nzer?= Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2008-01-23 at 13:42 +0100, Peter Zijlstra wrote: > Another question, do you have: > CONFIG_FAIR_GROUP_SCHED=y > > if so, does flipping that off have any effect? Yes. Here, I do the test of running 4 times the repro-case provided by Michel with nice 19 and a dd eating CPU with nice 0. Without this option, I get the dd at 100% and the nice 19 shells down below it with whatever is left of the CPUs. With this option, dd gets about 50% of one CPU and the niced processes still get most of the time. Ben.