From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: I/O bandwidth control on KVM Date: Sun, 02 Mar 2008 18:45:59 +0200 Message-ID: <47CAD9C7.90900@qumranet.com> References: <20080229.210531.226799765.ryov__28298.7898834564$1204287044$gmane$org@valinux.co.jp> <47CA2A7B.8000400@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Ryo Tsuruta , dm-devel@redhat.com, virtualization To: Anthony Liguori Return-path: In-Reply-To: <47CA2A7B.8000400@codemonkey.ws> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Anthony Liguori wrote: > Hi Ryo, > > Ryo Tsuruta wrote: > >> Hello all, >> >> I've implemented a block device which throttles block I/O bandwidth, >> which I called dm-ioband, and been trying to throttle I/O bandwidth on >> KVM environment. But unfortunately it doesn't work well, the number of >> issued I/Os is not according to the bandwidth setting. >> On the other hand, I got the good result when accessing directly to >> the local disk on the local machine. >> >> I'm not so familiar with KVM. Could anyone give me any advice? >> > > If you are using virtio drivers in the guest (which I presume you are > given the reference to /dev/vda), try using the following -drive syntax: > > -drive file=/dev/mapper/ioband1,if=virtio,boot=on,cache=off > > This will force the use of O_DIRECT. By default, QEMU does not open > with O_DIRECT so you'll see page cache effects. > > Good point. But IIRC cache=off is not limited to virtio? -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/