From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753422Ab1GLM0M (ORCPT ); Tue, 12 Jul 2011 08:26:12 -0400 Received: from mx2.fusionio.com ([66.114.96.31]:47683 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753247Ab1GLM0L (ORCPT ); Tue, 12 Jul 2011 08:26:11 -0400 X-ASG-Debug-ID: 1310473570-01de280c1ebfaa0001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <4E1C3D5E.1050601@fusionio.com> Date: Tue, 12 Jul 2011 14:26:06 +0200 From: Jens Axboe MIME-Version: 1.0 To: Shaohua Li CC: lkml , Vivek Goyal Subject: Re: [PATCH v2 0/3]CFQ: add think time check for service tree and group References: <1310434672.15392.283.camel@sli10-conroe> X-ASG-Orig-Subj: Re: [PATCH v2 0/3]CFQ: add think time check for service tree and group In-Reply-To: <1310434672.15392.283.camel@sli10-conroe> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1310473570 X-Barracuda-URL: http://10.101.1.181:8000/cgi-mod/mark.cgi X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.2.68703 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-07-12 03:37, Shaohua Li wrote: > Hi, > Currently when the last queue of a service tree/group is empty, CFQ > doesn't expire the queue. This is to allow requests from the tree/group > come soon, so tree/group doesn't miss its share. But if the think time > is big, the assumption isn't correct. idling the queue is just wasting > bandwidth. > > Originally I was hoping this can resolve Vivek's fsync issue, but it > doesn't. The fsync issue is caused by queue idling. But since think time > check only helps for think time above default queue idle time (8ms), > think time check doesn't help for the fsync issue. > > On the other hand, think time check is still helpful for queues with > think time. I had test case in follow patches show throughput > improvement without sacrifice tree/group shares. > > v1->v2: > 1. addressed some good comments from Vivek > 2. add more test to make sure the patches don't change behavior of > queues without think time. I applied 1-3, thanks. 1 was hand applied, since it didn't apply directly to for-3.1/core after I merged Justins patch to get rid of the meta data request special treatment. -- Jens Axboe