From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: [ATTEND] Want to attend LSF 2010 Date: Thu, 01 Jul 2010 14:10:06 -0400 Message-ID: <4C2CD9FE.8060707@redhat.com> References: <20100701180430.GD2705@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:41358 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750875Ab0GASIr (ORCPT ); Thu, 1 Jul 2010 14:08:47 -0400 In-Reply-To: <20100701180430.GD2705@redhat.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Vivek Goyal Cc: lsf10-pc@lists.linuxfoundation.org, linux-scsi@vger.kernel.org, James Bottomley On 07/01/2010 02:04 PM, Vivek Goyal wrote: > Resending this mail. This time also CCing linux-scsi mailing list. Sorry > for the duplicate copy. > > Hi, > > I wanted to attend LSF 2010. Sepcifically I was interested in discussing > couple of things. > > - CFQ performance issues on higher end storage > - Deadline outperforms CFQ on higher end storage (storage arrays > and also on host based hardware RAID). I was wondering if there > is a way to fix it or it is just design limitation. In the past > Jens had mentioned that he wants to get rid of deadline also and > be replaced with CFQ. Are we still targeting that and if yes, > how to achieve that (some kind of auto tuning). > > - Max bandwidth IO controller > - A basic proportional weight controller (blkio) based off CFQ is > now in. Now there is also a need to implement throttling/max > bandwidth controller. Wanted to get some ideas on how to go > go about it and what is the best place to impement it. Implement > it in CFQ or a new device mapper target or something else. > > Thanks > Vivek > Thanks Vivek, I know that this IO scheduling issue has been a hot issue for us in our performance testing. We would love to figure out how to get CFQ to displace deadline totally and definitely it would be very interesting to have a conversation around what needs done/what can be done. Vivek is a local, so no travel needed.... Thanks! Ric