From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: [PATCH] readahead:add blk_run_backing_dev Date: Wed, 27 May 2009 12:26:38 +0900 (JST) Message-ID: <20090527122540.6897.A69D9226@jp.fujitsu.com> References: <20090527025721.GA11153@localhost> <6.0.0.20.2.20090527120248.076abe38@172.19.0.2> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Cc: kosaki.motohiro@jp.fujitsu.com, Wu Fengguang , Andrew Morton , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "jens.axboe@oracle.com" To: Hisashi Hifumi Return-path: Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:51673 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755364AbZE0D0j (ORCPT ); Tue, 26 May 2009 23:26:39 -0400 In-Reply-To: <6.0.0.20.2.20090527120248.076abe38@172.19.0.2> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: > >> >The numbers look too small for a 7 disk RAID: > >> > > >> > > #dd if=testdir/testfile of=/dev/null bs=16384 > >> > > > >> > > -2.6.30-rc6 > >> > > 1048576+0 records in > >> > > 1048576+0 records out > >> > > 17179869184 bytes (17 GB) copied, 224.182 seconds, 76.6 MB/s > >> > > > >> > > -2.6.30-rc6-patched > >> > > 1048576+0 records in > >> > > 1048576+0 records out > >> > > 17179869184 bytes (17 GB) copied, 206.465 seconds, 83.2 MB/s > >> > > >> >I'd suggest you to configure the array properly before coming back to > >> >measuring the impact of this patch. > >> > >> > >> I created 16GB file to this disk array, and mounted to testdir, dd to > >this directory. > > > >I mean, you should get >300MB/s throughput with 7 disks, and you > >should seek ways to achieve that before testing out this patch :-) > > Throughput number of storage array is very from one product to another. > On my hardware environment I think this number is valid and > my patch is effective. Hifumi-san, if you really want to merge, you should reproduce this issue on typical hardware, I think.