Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756226AbZJ0Hpk (ORCPT ); Tue, 27 Oct 2009 03:45:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755572AbZJ0Hpj (ORCPT ); Tue, 27 Oct 2009 03:45:39 -0400 Received: from brick.kernel.dk ([93.163.65.50]:43975 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755376AbZJ0Hpj (ORCPT ); Tue, 27 Oct 2009 03:45:39 -0400 Date: Tue, 27 Oct 2009 08:45:43 +0100 From: Jens Axboe To: Shaohua Li Cc: "linux-kernel@vger.kernel.org" Subject: Re: [RFC]cfq-iosched: improve hw_tag detection Message-ID: <20091027074543.GQ10727@kernel.dk> References: <20091026091624.GA1169@sli10-desk.sh.intel.com> <20091026113555.GB10727@kernel.dk> <20091027005039.GA14819@sli10-desk.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091027005039.GA14819@sli10-desk.sh.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 935 Lines: 22 On Tue, Oct 27 2009, Shaohua Li wrote: > On Mon, Oct 26, 2009 at 07:35:55PM +0800, Jens Axboe wrote: > > On Mon, Oct 26 2009, Shaohua Li wrote: > > > If active queue hasn't enough requests and idle window opens, cfq will not > > > dispatch sufficient requests to hardware. In such situation, current code > > > will zero hw_tag. But this is because cfq doesn't dispatch enough requests > > > instead of hardware queue doesn't work. Don't zero hw_tag in such case. > > > > Thanks, that looks like a good fix. Curious, is this fixing some > > regression at your end? > No, just observed such issue when I play with cfq. OK thanks, just curious. I will apply it for 2.6.33. -- Jens Axboe -- 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/