From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbZHaRWJ (ORCPT ); Mon, 31 Aug 2009 13:22:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751365AbZHaRWI (ORCPT ); Mon, 31 Aug 2009 13:22:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15472 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751934AbZHaRWG (ORCPT ); Mon, 31 Aug 2009 13:22:06 -0400 Message-ID: <4A9C068C.2020008@redhat.com> Date: Mon, 31 Aug 2009 13:21:16 -0400 From: Rik van Riel User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Vivek Goyal CC: linux-kernel@vger.kernel.org, jens.axboe@oracle.com, containers@lists.linux-foundation.org, dm-devel@redhat.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, agk@redhat.com, akpm@linux-foundation.org, peterz@infradead.org, jmarchan@redhat.com, torvalds@linux-foundation.org, mingo@elte.hu Subject: Re: [PATCH 17/23] io-controller: anticipatory changes for hierarchical fair queuing References: <1251495072-7780-1-git-send-email-vgoyal@redhat.com> <1251495072-7780-18-git-send-email-vgoyal@redhat.com> In-Reply-To: <1251495072-7780-18-git-send-email-vgoyal@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vivek Goyal wrote: > This patch changes anticipatory scheduler to use queue scheduling code from > elevator layer. One can go back to old as by deselecting > CONFIG_IOSCHED_AS_HIER. Even with CONFIG_IOSCHED_AS_HIER=y, with-out any > other cgroup created, AS behavior should remain the same as old. > > o AS is a single queue ioschduler, that means there is one AS queue per group. > > o common layer code select the queue to dispatch from based on fairness, and > then AS code selects the request with-in group. > > o AS runs reads and writes batches with-in group. So common layer runs timed > group queues and with-in group time, AS runs timed batches of reads and > writes. > > o Note: Previously AS write batch length was adjusted synamically whenever > a W->R batch data direction took place and when first request from the > read batch completed. > > Now write batch updation takes place when last request from the write > batch has finished during W->R transition. > > o AS runs its own anticipation logic to anticipate on reads. common layer also > does the anticipation on the group if think time of the group is with-in > slice_idle. > > o Introduced few debugging messages in AS. > > Signed-off-by: Nauman Rafique > Signed-off-by: Vivek Goyal Acked-by: Rik van Riel