Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753811AbXIYNf3 (ORCPT ); Tue, 25 Sep 2007 09:35:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751821AbXIYNfW (ORCPT ); Tue, 25 Sep 2007 09:35:22 -0400 Received: from mail.gmx.net ([213.165.64.20]:46938 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751677AbXIYNfV (ORCPT ); Tue, 25 Sep 2007 09:35:21 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1+NX3EkolyNW070ap3S7N5vJxsiwafnfR8c59n0e9 T4v2SgwnB+LdMA Subject: Re: [git] CFS-devel, latest code From: Mike Galbraith To: vatsa@linux.vnet.ibm.com Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Peter Zijlstra , Dhaval Giani , Dmitry Adamushko , Andrew Morton In-Reply-To: <20070925125129.GA26310@linux.vnet.ibm.com> References: <20070924214537.GA18980@elte.hu> <1190700652.6482.7.camel@Homer.simpson.net> <1190705759.11910.10.camel@Homer.simpson.net> <1190709207.11226.6.camel@Homer.simpson.net> <20070925091331.GA22905@elte.hu> <20070925094440.GK26289@linux.vnet.ibm.com> <20070925094040.GA28391@elte.hu> <20070925101044.GA923@elte.hu> <20070925102855.GL26289@linux.vnet.ibm.com> <20070925103617.GA3426@elte.hu> <20070925125129.GA26310@linux.vnet.ibm.com> Content-Type: text/plain Date: Tue, 25 Sep 2007 15:35:17 +0200 Message-Id: <1190727317.11260.8.camel@Homer.simpson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2061 Lines: 53 On Tue, 2007-09-25 at 18:21 +0530, Srivatsa Vaddagiri wrote: > On Tue, Sep 25, 2007 at 12:36:17PM +0200, Ingo Molnar wrote: > > hm. perhaps this fixup in kernel/sched.c:set_task_cpu(): > > > > p->se.vruntime -= old_rq->cfs.min_vruntime - new_rq->cfs.min_vruntime; > > This definitely does need some fixup, even though I am not sure yet if > it will solve completely the latency issue. > > I tried the following patch. I *think* I see some improvement, wrt > latency seen when I type on the shell. Before this patch, I noticed > oddities like "kill -9 chew-max-pid" wont kill chew-max (it is queued in > runqueue waiting for a looong time to run before it can acknowledge > signal and exit). With this patch, I don't see such oddities ..So I am hoping > it fixes the latency problem you are seeing as well. http://lkml.org/lkml/2007/9/25/117 plus the below seems to be the SIlver Bullet for the latencies I was seeing. > Index: current/kernel/sched.c > =================================================================== > --- current.orig/kernel/sched.c > +++ current/kernel/sched.c > @@ -1039,6 +1039,8 @@ void set_task_cpu(struct task_struct *p, > { > int old_cpu = task_cpu(p); > struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); > + struct cfs_rq *old_cfsrq = task_cfs_rq(p), > + *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); > u64 clock_offset; > > clock_offset = old_rq->clock - new_rq->clock; > @@ -1051,7 +1053,8 @@ void set_task_cpu(struct task_struct *p, > if (p->se.block_start) > p->se.block_start -= clock_offset; > #endif > - p->se.vruntime -= old_rq->cfs.min_vruntime - new_rq->cfs.min_vruntime; > + p->se.vruntime -= old_cfsrq->min_vruntime - > + new_cfsrq->min_vruntime; > > __set_task_cpu(p, new_cpu); > } > > > -- > Regards, > vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/