On 2011-9-2 9:58, Zhi Yong Wu wrote: > 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. Ahh, I misunderstand you before. I thought you mentioned the blkio cgroup throttling interfaces. Ok, I think QEmu I/O throttling has similar semantic with blkio cgroup. So extending blkiotune command is preferred, IMHO. Thanks, Gui > > > Regards, > > Zhi Yong Wu > >> >> Thanks, >> Gui >> >>> >>> Stefan >>> >>> >> >> >> > > -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list