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 699E2DDE06 for ; Sat, 26 Jan 2008 16:16:53 +1100 (EST) Subject: Re: ppc32: Weird process scheduling behaviour with 2.6.24-rc From: Benjamin Herrenschmidt To: vatsa@linux.vnet.ibm.com In-Reply-To: <20080126050637.GA14177@linux.vnet.ibm.com> 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> <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> <20080126050637.GA14177@linux.vnet.ibm.com> Content-Type: text/plain Date: Sat, 26 Jan 2008 16:15:52 +1100 Message-Id: <1201324552.6815.165.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Ingo Molnar , Peter Zijlstra , Michel.=?iso-8859-1?Q?D=E4nzer_=3Cmichel=40tungstengraphics=2Ecom=3E?=@snowy.in.ibm.com Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > > Not that it seems that Michel reported far worse behaviour than what I > > saw, including pretty hickup'ish X behaviour even without the fair group > > scheduler compared to 2.6.23. It might be because he's running X niced > > to -1 (I leave X at 0 and let the scheduler deal with it in general) > > though. > > Hmm ..with X niced to -1, it should get more cpu power leading to a > better desktop experience. It depends as X can end up starving it's own clients, especially with a compositing manager or other fancy window manager... > Michel, > You had reported that commit 810e95ccd58d91369191aa4ecc9e6d4a10d8d0c8 > was the cause for this bad behavior. Do you see behavior change (from good->bad) > immediately after applying that patch during your bisect process? Also Michel, double check your .config in both cases. > I would prefer to have CONFIG_FAIR_GROUP_SCHED + > CONFIG_FAIR_CGROUP_SCHED on by default. Can you pls let me know how you > think is the desktop experience with that combination? I'm going to give that a try but unfortunately, it will have to wait until I'm back from LCA in a bit more than a week. Ben.