Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753590AbZDVAt3 (ORCPT ); Tue, 21 Apr 2009 20:49:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752541AbZDVAtU (ORCPT ); Tue, 21 Apr 2009 20:49:20 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:50704 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752417AbZDVAtU (ORCPT ); Tue, 21 Apr 2009 20:49:20 -0400 Message-ID: <49EE69C2.9030908@cn.fujitsu.com> Date: Wed, 22 Apr 2009 08:50:10 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Vivek Goyal CC: Mike Snitzer , device-mapper development , nauman@google.com, fernando@oss.ntt.co.jp, linux-kernel@vger.kernel.org, jmoyer@redhat.com, jens.axboe@oracle.com, agk@redhat.com, balbir@linux.vnet.ibm.com Subject: Re: dm-ioband: Test results. References: <20090420.172959.193682665.ryov@valinux.co.jp> <20090421.210614.112619728.ryov@valinux.co.jp> <20090421.211051.183023683.ryov@valinux.co.jp> <20090421135723.GA13953@redhat.com> <20090421141607.GA22619@redhat.com> In-Reply-To: <20090421141607.GA22619@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2619 Lines: 53 Vivek Goyal wrote: > On Tue, Apr 21, 2009 at 09:57:23AM -0400, Mike Snitzer wrote: >> On Tue, Apr 21 2009 at 8:10am -0400, >> Ryo Tsuruta wrote: >> >>> Hi Nauman, >>> >>>>> The real question is, once you create a version of dm-ioband that >>>>> co-operates with CFQ scheduler, how that solution would compare with >>>>> the patch set Vivek has posted? In my opinion, we need to converge to >>>>> one solution as soon as possible, so that we can work on it together >>>>> to refine and test it. >>>> I think I can do some help for your work. but I want to continue the >>>> development of dm-ioband, because dm-ioband actually works well and >>>> I think it has some advantages against other IO controllers. >>>> - It can use without cgroup. >>>> - It can control bandwidth on a per partition basis. >>>> - The driver module can be replaced without stopping the system. >>> In addition, dm-ioband can run on the RHEL5. >> RHEL5 compatibility does not matter relative to merging an I/O bandwidth >> controller upstream. So both the "can [be] use without cgroup" and "can >> run on RHEL5" features do not help your cause of getting dm-ioband >> merged upstream. In fact these features serve as distractions. > > Exactly. I don't think that "it can be used without cgroup" is a feature > or advantage. To me it is a disadvantage and should be fixed. cgroup is > standard mechanism to group tasks arbitrarily and we should use that to make > things working instead of coming up with own ways of grouping things and > terming it as advantage. > I agree. And for the case of cpu scheduler, there are user group scheduler and cgroup group scheduler, but Peter said he would like to see user group scheduler to be removed. > What do you mean by "The driver module can be replaced without stopping > the system"? I guess you mean that one does not have to reboot the system > to remove ioband device? So if one decides to not use the cgroup, then > one shall have to remove the ioband devices, remount the filesystems and > restart the application? > > With cgroup approach, if one does not want things to be classified, a user > can simply move all the tasks to root group and things will be fine. No > remounting, no application stopping etc. So this also does not look like > an advantage instead sounds like an disadvantage. > > Thanks > Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/