Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756239AbZDFNE0 (ORCPT ); Mon, 6 Apr 2009 09:04:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754308AbZDFNER (ORCPT ); Mon, 6 Apr 2009 09:04:17 -0400 Received: from brick.kernel.dk ([93.163.65.50]:59639 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753880AbZDFNEQ (ORCPT ); Mon, 6 Apr 2009 09:04:16 -0400 Date: Mon, 6 Apr 2009 15:04:14 +0200 From: Jens Axboe To: linux-kernel@vger.kernel.org Cc: tytso@mit.edu, torvalds@linux-foundation.org Subject: Re: [PATCH 0/8][RFC] IO latency/throughput fixes Message-ID: <20090406130414.GX5178@kernel.dk> References: <1239022088-29002-1-git-send-email-jens.axboe@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1239022088-29002-1-git-send-email-jens.axboe@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1812 Lines: 70 On Mon, Apr 06 2009, Jens Axboe wrote: > Hi, > > This is a set of patches that I worked on today in the hopes > of furthering the latency goals and at least fixing some of > the write regression with fwrite + fsync that current -git > is suffering from. > > I haven't done any latency tests yet, I'm just tossing this > out there so we can collaborate on improving things. What I > did test was the silly fwrite() + fsync() loop test, which > is a LOT slower in current -git that it used to be. The test > is basically: > > while (nr--) { > f = fopen(); > fprintf(f, "Some data here\n"); > fsync(fileno(f)); > fclose(f); > } > > which (for nr == 2000) takes 16 seconds in -git, completes > in 0.9s with the patches. Ran the fsync-tester [1]. Drive is a 3-4 years old SATA drive, fs is ext3/writeback. IO scheduler is CFQ. fsync time: 0.0402s fsync time: 0.6572s fsync time: 0.3187s fsync time: 0.2901s fsync time: 0.1478s fsync time: 0.4158s fsync time: 0.2815s fsync time: 0.3216s fsync time: 0.1604s fsync time: 0.1929s fsync time: 0.2413s fsync time: 0.2138s fsync time: 0.2441s fsync time: 0.2785s fsync time: 0.2640s And with Linus torture dd running in the background: fsync time: 0.0109s fsync time: 0.5236s fsync time: 1.2108s fsync time: 0.2999s fsync time: 1.5286s fsync time: 0.2549s fsync time: 0.4164s fsync time: 1.1586s fsync time: 1.6630s fsync time: 0.6949s fsync time: 1.0102s fsync time: 0.3715s fsync time: 0.6553s [1] http://www.gossamer-threads.com/lists/engine?do=post_attachment;postatt_id=33847;list=linux -- 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/