From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 955FE6B004D for ; Mon, 22 Jun 2009 12:51:02 -0400 (EDT) Date: Mon, 22 Jun 2009 17:52:36 +0100 From: Mel Gorman Subject: Re: Re: Re: Performance degradation seen after using one list for hot/cold pages. Message-ID: <20090622165236.GE3981@csn.ul.ie> References: <20626261.51271245670323628.JavaMail.weblogic@epml20> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20626261.51271245670323628.JavaMail.weblogic@epml20> Sender: owner-linux-mm@kvack.org To: NARAYANAN GOPALAKRISHNAN Cc: KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "cl@linux-foundation.org" , "akpm@linux-foundation.org" , "kosaki.motohiro@jp.fujitsu.com" List-ID: On Mon, Jun 22, 2009 at 11:32:03AM +0000, NARAYANAN GOPALAKRISHNAN wrote: > Hi, > > We are running on VFAT. > We are using iozone performance benchmarking tool (http://www.iozone.org/src/current/iozone3_326.tar) for testing. > > The parameters are > /iozone -A -s10M -e -U /tmp -f /tmp/iozone_file > > Our block driver requires requests to be merged to get the best performance. > This was not happening due to non-contiguous pages in all kernels >= 2.6.25. > Ok, by the looks of things, all the aio_read() requests are due to readahead as opposed to explicit AIO requests from userspace. In this case, nothing springs to mind that would avoid excessive requests for cold pages. It looks like the simpliest solution is to go with the patch I posted. Does anyone see a better alternative that doesn't branch in rmqueue_bulk() or add back the hot/cold PCP lists? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org