From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750995AbWFAO4q (ORCPT ); Thu, 1 Jun 2006 10:56:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751017AbWFAO4q (ORCPT ); Thu, 1 Jun 2006 10:56:46 -0400 Received: from gateway.argo.co.il ([194.90.79.130]:53518 "EHLO argo2k.argo.co.il") by vger.kernel.org with ESMTP id S1750994AbWFAO4p (ORCPT ); Thu, 1 Jun 2006 10:56:45 -0400 Message-ID: <447F0023.8090206@argo.co.il> Date: Thu, 01 Jun 2006 17:56:35 +0300 From: Avi Kivity User-Agent: Thunderbird 1.5.0.2 (X11/20060501) MIME-Version: 1.0 To: Jens Axboe CC: Mark Lord , Linus Torvalds , Nick Piggin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, mason@suse.com, andrea@suse.de, hugh@veritas.com Subject: Re: NCQ performance (was Re: [rfc][patch] remove racy sync_page?) References: <20060601131921.GH4400@suse.de> In-Reply-To: <20060601131921.GH4400@suse.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 01 Jun 2006 14:56:43.0608 (UTC) FILETIME=[98BC8D80:01C6858B] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe wrote: > > Ok, I decided to rerun a simple random read work load (with fio), using > depths 1 and 32. The test is simple - it does random reads all over the > drive size with 4kb block sizes. The reads are O_DIRECT. The test > pattern was set to repeatable, so it's going through the same workload. > The test spans the first 32G of the drive and runtime is capped at 20 > seconds. > Did you modify the iodepth given to the test program, or to the drive? If the former, then some of the performance increase came from the Linux elevator. Ideally exactly the same test would be run with the just the drive parameters changed. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.