From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 01/10] Documentation Date: Thu, 12 Mar 2009 00:11:46 -0700 Message-ID: <20090312001146.74591b9d.akpm@linux-foundation.org> References: <1236823015-4183-1-git-send-email-vgoyal@redhat.com> <1236823015-4183-2-git-send-email-vgoyal@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1236823015-4183-2-git-send-email-vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Vivek Goyal Cc: oz-kernel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, paolo.valente-rcYM44yAMweonA0d6jMUrA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dhaval-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, fchecconi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, arozansk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, fernando-w0OK63jvRlAuJ+9fw/WgBHgSJqDPrsil@public.gmane.org, balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org List-Id: containers.vger.kernel.org On Wed, 11 Mar 2009 21:56:46 -0400 Vivek Goyal wrote: > +Currently "current" task > +is used to determine the cgroup (hence io group) of the request. Down the > +line we need to make use of bio-cgroup patches to map delayed writes to > +right group. You handled this problem pretty neatly! It's always been a BIG problem for all the io-controlling schemes, and most of them seem to have "handled" it in the above way :( But for many workloads, writeback is the majority of the IO and it has always been the form of IO which has caused us the worst contention and latency problems. So I don't think that we can proceed with _anything_ until we at least have a convincing plan here. Also.. there are so many IO controller implementations that I've lost track of who is doing what. I do have one private report here that Andreas's controller "is incredibly productive for us and has allowed us to put twice as many users per server with faster times for all users". Which is pretty stunning, although it should be viewed as a condemnation of the current code, I'm afraid. So my question is: what is the definitive list of proposed-io-controller-implementations and how do I cunningly get all you guys to check each others homework? :) From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753764AbZCLHT5 (ORCPT ); Thu, 12 Mar 2009 03:19:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750943AbZCLHTs (ORCPT ); Thu, 12 Mar 2009 03:19:48 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38816 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835AbZCLHTr (ORCPT ); Thu, 12 Mar 2009 03:19:47 -0400 Date: Thu, 12 Mar 2009 00:11:46 -0700 From: Andrew Morton To: Vivek Goyal Cc: nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, jens.axboe@oracle.com, ryov@valinux.co.jp, fernando@intellilink.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, arozansk@redhat.com, jmoyer@redhat.com, oz-kernel@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, menage@google.com, peterz@infradead.org Subject: Re: [PATCH 01/10] Documentation Message-Id: <20090312001146.74591b9d.akpm@linux-foundation.org> In-Reply-To: <1236823015-4183-2-git-send-email-vgoyal@redhat.com> References: <1236823015-4183-1-git-send-email-vgoyal@redhat.com> <1236823015-4183-2-git-send-email-vgoyal@redhat.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Mar 2009 21:56:46 -0400 Vivek Goyal wrote: > +Currently "current" task > +is used to determine the cgroup (hence io group) of the request. Down the > +line we need to make use of bio-cgroup patches to map delayed writes to > +right group. You handled this problem pretty neatly! It's always been a BIG problem for all the io-controlling schemes, and most of them seem to have "handled" it in the above way :( But for many workloads, writeback is the majority of the IO and it has always been the form of IO which has caused us the worst contention and latency problems. So I don't think that we can proceed with _anything_ until we at least have a convincing plan here. Also.. there are so many IO controller implementations that I've lost track of who is doing what. I do have one private report here that Andreas's controller "is incredibly productive for us and has allowed us to put twice as many users per server with faster times for all users". Which is pretty stunning, although it should be viewed as a condemnation of the current code, I'm afraid. So my question is: what is the definitive list of proposed-io-controller-implementations and how do I cunningly get all you guys to check each others homework? :)