Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755272Ab0ASWeL (ORCPT ); Tue, 19 Jan 2010 17:34:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753739Ab0ASWeK (ORCPT ); Tue, 19 Jan 2010 17:34:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49816 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753142Ab0ASWeF (ORCPT ); Tue, 19 Jan 2010 17:34:05 -0500 Date: Tue, 19 Jan 2010 17:33:56 -0500 From: Vivek Goyal To: "Li, Shaohua" Cc: Gui Jianfeng , Corrado Zoccolo , "jens.axboe@oracle.com" , "linux-kernel@vger.kernel.org" , "jmoyer@redhat.com" , "yanmin_zhang@linux.intel.com" Subject: Re: [PATCH]cfq-iosched: don't stop async queue with async requests pending Message-ID: <20100119223356.GC4992@redhat.com> References: <20100113074442.GA10492@sli10-desk.sh.intel.com> <4e5e476b1001130018n2ad9e830s4a20d922abd4c7bb@mail.gmail.com> <20100113082322.GA24345@sli10-desk.sh.intel.com> <20100113111341.GB3087@redhat.com> <20100114034150.GA3922@sli10-desk.sh.intel.com> <4B4EAB39.1070301@cn.fujitsu.com> <20100114061731.GA23590@sli10-desk.sh.intel.com> <20100114110902.GA15559@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1375 Lines: 34 On Tue, Jan 19, 2010 at 08:52:01AM +0800, Li, Shaohua wrote: [..] > >Yes cfq_should_idle() can check for async queue and return false. > > > >Regarding group loosing fair share, currently all async queues are in root > >group and not in individual groups, so this particular change should not > >affect a lot. We will continue to idle on sync-idle and sync-noidle > >service tree. Only async service tree is the exception. > > > >Once we introduce per group async queue in future, we shall have to come > >up with something else, if need be. > > > >So keep this as a separate patch. I think in the presence of mixed > >workload, (readers and buffered writers), it might give little performance > >boost. We need to test it though. > Ok, if you thought this method doesn't break group, here is the updated > patch. I'm sorry to send the attached patch, my mailbox has trouble. Hi Shaohua, I did some testing on cfq group functionality and I did not see any significant impact of this patch. I am yet to write some test cases for mixed workload testing and see the impact of this patch. Will get back to you soon. Thanks Vivek -- 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/