Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753642AbZKLR3i (ORCPT ); Thu, 12 Nov 2009 12:29:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753504AbZKLR3i (ORCPT ); Thu, 12 Nov 2009 12:29:38 -0500 Received: from cantor2.suse.de ([195.135.220.15]:36700 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753399AbZKLR3h (ORCPT ); Thu, 12 Nov 2009 12:29:37 -0500 Date: Thu, 12 Nov 2009 18:29:41 +0100 From: Jan Kara To: Jeff Moyer Cc: Jan Kara , jens.axboe@oracle.com, LKML , Chris Mason , Andrew Morton , Mike Galbraith , mszeredi@suse.de Subject: Re: Performance regression in IO scheduler still there Message-ID: <20091112172941.GK14528@duck.suse.cz> References: <20091026172012.GC7233@duck.suse.cz> <20091111141031.GA21511@duck.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1227 Lines: 31 On Wed 11-11-09 12:43:30, Jeff Moyer wrote: > Jan Kara writes: > > > Sadly, I don't see the improvement you can see :(. The numbers are the > > same regardless low_latency set to 0: > > 2.6.32-rc5 low_latency = 0: > > 37.39 36.43 36.51 -> 36.776667 0.434920 > > But my testing environment is a plain SATA drive so that probably > > explains the difference... > > I just retested (10 runs for each kernel) on a SATA disk with no NCQ > support and I could not see a difference. I'll try to dig up a disk > that support NCQ. Is that what you're using for testing? I don't think I am. How do I find out? > 2.6.29 2.6.32-rc6,low_latency=0 > ---------------------------------- > Average: 34.6648 34.4475 > Pop.Std.Dev.: 0.55523 0.21981 Hmm, strange. Miklos Szeredi tried tiobench on his machine and he also saw the regression. I'll try to think what could make the difference. Honza -- Jan Kara SUSE Labs, CR -- 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/