From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752763Ab0F1Syj (ORCPT ); Mon, 28 Jun 2010 14:54:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30413 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751896Ab0F1Syi (ORCPT ); Mon, 28 Jun 2010 14:54:38 -0400 From: Jeff Moyer To: Jens Axboe Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] cfq: always return false from should_idle if slice_idle is set to zero References: <1277149789-4493-1-git-send-email-jmoyer@redhat.com> <1277149789-4493-2-git-send-email-jmoyer@redhat.com> <4C1FC4CA.7030007@kernel.dk> <4C28EF04.7040309@kernel.dk> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Mon, 28 Jun 2010 14:54:35 -0400 In-Reply-To: <4C28EF04.7040309@kernel.dk> (Jens Axboe's message of "Mon, 28 Jun 2010 20:50:44 +0200") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe writes: > On 28/06/10 20.41, Jeff Moyer wrote: >> Jens Axboe writes: >> >>> On 21/06/10 21.49, Jeff Moyer wrote: >>>> Hi, >>>> >>>> In testing a competing fsync-ing process and a sequential reader on >>>> mid-grade storage, I found that cfq was incapable of achieving the I/O >>>> rates of deadline, no matter how it was tuned. Investigation, and insight >>>> from Vivek (mostly the latter), led to identifying that we were still >>>> idling for the last queue in the service tree. >>>> >>>> Modifying cfq_should_idle to not idle when slice_idle is set to zero got >>>> us much closer to the performance of deadline for this workload. I have >>>> one follow-on patch that gets us on-par with deadline, but I think this >>>> patch stands alone. >>>> >>>> Comments, as always, are appreciated. >>> >>> This looks good. >> >> So.... applied to which branch? > > Not applied yet, unless I explicitly say it's applied, then it's not > necessarily in any public git tree yet. But this will go into .35. OK, thanks for the clarification. Cheers, Jeff