From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760432AbYG3Kcq (ORCPT ); Wed, 30 Jul 2008 06:32:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753063AbYG3Kci (ORCPT ); Wed, 30 Jul 2008 06:32:38 -0400 Received: from casper.infradead.org ([85.118.1.10]:54185 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752756AbYG3Kch (ORCPT ); Wed, 30 Jul 2008 06:32:37 -0400 Subject: Re: [RFT][PATCH] sched: scale sysctl_sched_shares_ratelimit with nr_cpus From: Peter Zijlstra To: David Miller Cc: vatsa@linux.vnet.ibm.com, dhaval@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, mingo@elte.hu In-Reply-To: <20080730.032930.55051878.davem@davemloft.net> References: <1217413511.8157.7.camel@twins> <20080730.032930.55051878.davem@davemloft.net> Content-Type: text/plain Date: Wed, 30 Jul 2008 12:32:29 +0200 Message-Id: <1217413949.8157.12.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2008-07-30 at 03:29 -0700, David Miller wrote: > From: Peter Zijlstra > Date: Wed, 30 Jul 2008 12:25:11 +0200 > > > Dhaval, Vatsa, > > > > Could you guys give this patch a spin on the big iron and possibly tune > > the default shares_ratelimit value to give satisfactory fairness on your > > large machines while considering the overhead? > > > > > > --- > > Subject: sched: scale sysctl_sched_shares_ratelimit with nr_cpus > > > > David reported that his Niagra spend a little too much time in > > tg_shares_up(), which considering he has a large cpu count makes sense. > > > > So scale the ratelimit value with the number of cpus like we do for > > other controls as well. > > > > Reported-by: David Miller > > Signed-off-by: Peter Zijlstra > > This turned out to be a false theory, and the lockdep problem I > reported the past few days was the real culprit. > > The rebalancing et al. showing up in my debugging dumps was > just chance and not even consistent. Ah, still I think the proposed change makes sense, but lets wait for some test results from Dhaval and or Vatsa.. ;-)