From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 2F936B710B for ; Fri, 3 Jul 2009 10:34:43 +1000 (EST) Received: from e8.ny.us.ibm.com (e8.ny.us.ibm.com [32.97.182.138]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e8.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 76329DDD0B for ; Fri, 3 Jul 2009 10:34:42 +1000 (EST) Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e8.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n630Nn4T008730 for ; Thu, 2 Jul 2009 20:23:49 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n630YcXk253910 for ; Thu, 2 Jul 2009 20:34:38 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n630YcI0013642 for ; Thu, 2 Jul 2009 20:34:38 -0400 Date: Thu, 2 Jul 2009 20:34:04 -0400 From: Josh Boyer To: Benjamin Herrenschmidt Subject: Re: Preemption question (4xx related) Message-ID: <20090703003403.GA23124@zod.rchland.ibm.com> References: <24271342.post@talk.nabble.com> <1246486393.14483.14.camel@pasglop> <20090702001450.GF6189@zod.rchland.ibm.com> <1246519992.7551.1.camel@pasglop> <20090702111246.GG6189@zod.rchland.ibm.com> <1246574460.7551.6.camel@pasglop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1246574460.7551.6.camel@pasglop> Cc: linuxppc-dev@ozlabs.org, Felix Radensky List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Jul 03, 2009 at 08:41:00AM +1000, Benjamin Herrenschmidt wrote: >On Thu, 2009-07-02 at 07:12 -0400, Josh Boyer wrote: >> On Thu, Jul 02, 2009 at 05:33:12PM +1000, Benjamin Herrenschmidt wrote: >> >On Wed, 2009-07-01 at 20:14 -0400, Josh Boyer wrote: >> > >> >> I've toyed with that idea myself. I keep coming back to the fact that you need >> >> a workload that would really leverage it, and I don't have one at the moment. >> > >> >To some extent that's true but just turning full preemption including >> >kernel side with all the associated debug bits and lockdep should make a >> >whole bunch of things show up even with ordinary workloads. >> >> I can look at doing that for ppc44x_defconfig. I'll be honest and say I don't >> expect it to go well, particularly with lockdep :). >> >> >For 440 tend to boot an ubuntu distro off NFS root with all X & DRI 3D >> >etc... and then run compiz :-) >> >> Yes. Because that's a totally realistic workload for a 440. I'm surprised you >> don't have a p595 machine acting as your home router too! ;) > >It doesn't need to be realistic. In fact, a "realistic" workload is the >worst thing to test with because it won't exercise all the "uncommon" >code path which are the ones likely to bite. > >So yesm it's not a "realistic" workload, but it's a good "torture" >workload to find bugs. It was a joke. But yes, you make perfectly valid points :) josh