From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757824AbaFZSFY (ORCPT ); Thu, 26 Jun 2014 14:05:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1979 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750731AbaFZSFX (ORCPT ); Thu, 26 Jun 2014 14:05:23 -0400 From: Jeff Moyer To: Mel Gorman Cc: Linux Kernel , Linux-MM , Linux-FSDevel , Johannes Weiner , Jens Axboe , Dave Chinner Subject: Re: [PATCH 6/6] cfq: Increase default value of target_latency References: <1403683129-10814-1-git-send-email-mgorman@suse.de> <1403683129-10814-7-git-send-email-mgorman@suse.de> <20140626161955.GH10819@suse.de> <20140626174500.GI10819@suse.de> 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: Thu, 26 Jun 2014 14:04:34 -0400 In-Reply-To: <20140626174500.GI10819@suse.de> (Mel Gorman's message of "Thu, 26 Jun 2014 18:45:00 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mel Gorman writes: >> And we should probably run our standard set of I/O exercisers at the >> very least. But, like I said, it seems like wasted effort. >> > > Out of curiousity, what do you consider to be the standard set of I/O > exercisers? Yes, that was vague, sorry. I was referring to any io generator that will perform sequential and random I/O (writes, re-writes, reads, random writes, random reads, strided reads, backwards reads, etc). We use iozone internally, testing both buffered and direct I/O, varying file and record sizes and across multiple file systems. Data sets that fall inside of the page cache tend to have a high standard deviation, so, as an I/O guy, I ignore those. ;-) Cheers, Jeff