On Fri, Sep 02, 2011 at 09:16:59AM +0800, Gui Jianfeng wrote: >Message-ID: <4E602E8B.6010900@xxxxxxxxxxxxxx> >Date: Fri, 02 Sep 2011 09:16:59 +0800 >From: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx> >User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:6.0) Gecko/20110812 > Thunderbird/6.0 >MIME-Version: 1.0 >To: Stefan Hajnoczi <stefanha@xxxxxxxxx>, Zhi Yong Wu > <wuzhy@xxxxxxxxxxxxxxxxxx> >References: <20110901050531.GB17963@xxxxxxxxxxxxxx> > <20110901081149.GB14245@stefanha-thinkpad.localdomain> >In-Reply-To: <20110901081149.GB14245@stefanha-thinkpad.localdomain> >X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July > 25, 2010) at 2011-09-02 09:15:49, Serialize by Router on > mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-09-02 09:15:52, > Serialize complete at 2011-09-02 09:15:52 >Content-Transfer-Encoding: 7bit >Content-Type: text/plain; charset=ISO-8859-1 >X-detected-operating-system: by eggs.gnu.org: FreeBSD 6.x (1) >X-Received-From: 222.73.24.84 >Cc: libvir-list@xxxxxxxxxx, hutao@xxxxxxxxxxxxxx, qemu-devel@xxxxxxxxxx, > zwu.kernel@xxxxxxxxx, agl@xxxxxxxxxx >Subject: Re: [Qemu-devel] [RFC] block I/O throttling: how to enable in > libvirt >X-BeenThere: qemu-devel@xxxxxxxxxx >X-Mailman-Version: 2.1.14 >Precedence: list >List-Id: <qemu-devel.nongnu.org> >List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>, > <mailto:qemu-devel-request@xxxxxxxxxx?subject=unsubscribe> >List-Archive: </archive/html/qemu-devel> >List-Post: <mailto:qemu-devel@xxxxxxxxxx> >List-Help: <mailto:qemu-devel-request@xxxxxxxxxx?subject=help> >List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>, > <mailto:qemu-devel-request@xxxxxxxxxx?subject=subscribe> >X-Mailman-Copy: yes >Errors-To: qemu-devel-bounces+wuzhy=linux.vnet.ibm.com@xxxxxxxxxx >Sender: qemu-devel-bounces+wuzhy=linux.vnet.ibm.com@xxxxxxxxxx >X-Brightmail-Tracker: AAAAAA== >X-Xagent-From: guijianfeng@xxxxxxxxxxxxxx >X-Xagent-To: wuzhy@xxxxxxxxxxxxxxxxxx >X-Xagent-Gateway: vmsdvm9.vnet.ibm.com (XAGENTU at VMSDVM9) > >On 2011-9-1 16:11, Stefan Hajnoczi wrote: >> On Thu, Sep 01, 2011 at 01:05:31PM +0800, Zhi Yong Wu wrote: >>> On Wed, Aug 31, 2011 at 08:18:19AM +0100, Stefan Hajnoczi wrote: >>>> On Tue, Aug 30, 2011 at 2:46 PM, Adam Litke <agl@xxxxxxxxxx> wrote: >>>>> On Tue, Aug 30, 2011 at 09:53:33AM +0100, Stefan Hajnoczi wrote: >>>>>> I/O throttling can be applied independently to each -drive attached to >>>>>> a guest and supports throughput/iops limits. For more information on >>>>>> this QEMU feature and a comparison with blkio-controller, see Ryan >>>>>> Harper's KVM Forum 2011 presentation: >>>>> >>>>>> http://www.linux-kvm.org/wiki/images/7/72/2011-forum-keep-a-limit-on-it-io-throttling-in-qemu.pdf >>>>> >>>>> From the presentation, it seems that both the cgroups method the the qemu method >>>>> offer comparable control (assuming a block device) so it might possible to apply >>>>> either method from the same API in a transparent manner. Am I correct or are we >>>>> suggesting that the Qemu throttling approach should always be used for Qemu >>>>> domains? >>>> >>>> QEMU I/O throttling does not provide a proportional share mechanism. >>>> So you cannot assign weights to VMs and let them receive a fraction of >>>> the available disk time. That is only supported by cgroups >>>> blkio-controller because it requires a global view which QEMU does not >>>> have. >>>> >>>> So I think the two are complementary: >>>> >>>> If proportional share should be used on a host block device, use >>>> cgroups blkio-controller. >>>> Otherwise use QEMU I/O throttling. >>> Stefan, >>> >>> Do you agree with introducing one new libvirt command blkiothrottle now? >>> If so, i will work on the code draft to make it work. >> >> No, I think that the blkiotune command should be extended to support >> QEMU I/O throttling. This is not new functionality, we already have >> cgroups blkio-controller support today. Therefore I think it makes >> sense to keep a unified interface instead of adding a new command. > >Agreed. >Proportional controlling interfaces and throttling interfaces are all >the same cgroup subsystem. So Just extend blkiotune to add new options >to support throttling tuning. Hi, Gui, QEMU block I/O throttling is not relative to cgroup subsystem, i think. anyway, thanks for your sugguests. Regards, Zhi Yong Wu > >Thanks, >Gui > >> >> Stefan >> >> > > > -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list