Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753371AbZD2Dai (ORCPT ); Tue, 28 Apr 2009 23:30:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752001AbZD2Da3 (ORCPT ); Tue, 28 Apr 2009 23:30:29 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:59680 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751790AbZD2Da2 (ORCPT ); Tue, 28 Apr 2009 23:30:28 -0400 Date: Wed, 29 Apr 2009 09:00:20 +0530 From: Bharata B Rao To: KOSAKI Motohiro Cc: LKML , Balaji Rao , Dhaval Giani , KAMEZAWA Hiroyuki , Peter Zijlstra , Balbir Singh , Ingo Molnar , Martin Schwidefsky , seto.hidetoshi@jp.fujitsu.com Subject: Re: [PATCH] cpuacct: VIRT_CPU_ACCOUNTING don't prevent percpu cputime count Message-ID: <20090429033020.GB3408@in.ibm.com> Reply-To: bharata@linux.vnet.ibm.com References: <20090428165203.EBD5.A69D9226@jp.fujitsu.com> <20090428103701.GE3825@in.ibm.com> <20090429110629.4B05.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090429110629.4B05.A69D9226@jp.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1370 Lines: 32 On Wed, Apr 29, 2009 at 11:31:14AM +0900, KOSAKI Motohiro wrote: > > > > > > BTW, did you observe any real problem with the percpu counter spinlock ? > > > > > > > > > > No. > > > > > I review percpu_counter() caller recently and it seems stragen usage. > > > > > > > > > > > > > I should have phrased the question better ... > > > > > > > > So have you found any performance degradation with any benchmarks/workloads > > > > on archs which define VIRT_CPU_ACCOUNTING due to percpu_counter spinlock > > > > being taken on every tick ? If the answer is no, don't you think we could > > > > wait before making the kind of change you are proposing ? > > > > > > maybe, I don't understand your point. > > > > My point is, let us not make this change if it is not a real problem that > > has been observed on archs which define VIRT_CPU_ACCOUNTING. > > It's nice joke. but not constructive. I was only asking you if you have seen any real life problem with this and you said no. In that context, if I re-read my above point, I think I should have a pretty good sense of humour to consider it as joke :) Regards, Bharata. -- 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/