From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54853) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UOqEJ-00005V-Td for qemu-devel@nongnu.org; Sun, 07 Apr 2013 10:06:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UOqEC-0007Jt-UT for qemu-devel@nongnu.org; Sun, 07 Apr 2013 10:05:59 -0400 Received: from mail-oa0-f42.google.com ([209.85.219.42]:42005) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UOqEC-0007Jb-Nw for qemu-devel@nongnu.org; Sun, 07 Apr 2013 10:05:52 -0400 Received: by mail-oa0-f42.google.com with SMTP id i18so5449718oag.29 for ; Sun, 07 Apr 2013 07:05:51 -0700 (PDT) From: Anthony Liguori In-Reply-To: <3A6795EA1206904E94BEC8EF9DF109AE05D381F9@szxeml510-mbx.china.huawei.com> References: <20130327154149.GA3769@stefanha-thinkpad.muc.redhat.com> <67ACAA1D2D06420ABEB53D364FCB6631@gmail.com> <3A6795EA1206904E94BEC8EF9DF109AE05D381F9@szxeml510-mbx.china.huawei.com> Date: Sun, 07 Apr 2013 09:05:47 -0500 Message-ID: <874nfio2pw.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] question about performance of dataplane List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Zhangleiqiang , Stefan Hajnoczi , "stefanha@redhat.com" Cc: "Luohao (brian)" , "qemu-devel@nongnu.org" , Haofeng , leiqzhang Zhangleiqiang writes: > Hi, Stefan=EF=BC=9A > > I have done some testing to compare the performance of dataplane and non= -dataplane. But the result did not meet my expectations, the performance o= f disk with dataplane enabled did not have advantage over non-dataplane.=20 > > The following contains the environment info and testing results. Does= my testing method or testing environment have something wrong ? Could you= give me some advice? I can provide more information if need. > > > 1. Environment: > a). Qemu 1.4 master branch > b). kernel: 3.5.0-2.fc17.x86_64 > c). virtual disks location: the same local SATA harddisk > with ext4 fs I doubt you'll see any performance difference with a single SATA drive. There's no real parallelism possible as you have exactly one spindle available. > datasize/RW_Ratio IOPS_dataplane IOPS_non_dataplane MBPS_dataplane MBPS_= non_dataplane > 16K/0% 294.094948 293.609606 4.595234 4.58765 > 16K/25% 283.096745 281.649258 4.423387 4.40077 > 16K/75% 316.039801 309.585336 4.938122 4.837271 > 32K/0% 257.529537 258.806128 8.047798 8.087692 > 32K/25% 253.729281 253.756673 7.92904 7.929896 > 32K/75% 292.384568 280.991434 9.137018 8.780982 > 4K/0% 321.599352 324.116063 1.256247 1.266078 > 4K/25% 309.906635 309.294278 1.210573 1.208181 > 4K/75% 350.168882 > 350.772329 1.367847 > 1.370204 You are getting 300 MB/s to a single SATA disk? I strongly suspect you are seeing cache interaction. I'd suggest disabling WCE on the disk if you're going to benchmark like this. I'd also guess 300 MB/s is what you're maxing out at with native too. So presumably normal virtio-blk is already getting close to native performance. dataplane certainly isn't going to give you better than native performance :-) Regards, Anthony Liguori > > > > ---------- > Leiqzhang > > Best Regards > > >> =E5=8F=91=E4=BB=B6=E4=BA=BA: qemu-devel-bounces+zhangleiqiang=3Dhuawei.c= om@nongnu.org [mailto:qemu-devel-bounces+zhangleiqiang=3Dhuawei.com@nongnu.= org] =E4=BB=A3=E8=A1=A8 leiqzhang >> =E5=8F=91=E9=80=81=E6=97=B6=E9=97=B4: 2013=E5=B9=B43=E6=9C=8828=E6=97=A5= 12:03 >> =E6=94=B6=E4=BB=B6=E4=BA=BA: Stefan Hajnoczi >> =E6=8A=84=E9=80=81: pbonzini@redhat.com; qemu-devel@nongnu.org; stefanha= @redhat.com; =E5=BC=A0 =E7=A3=8A=E5=BC=BA >> =E4=B8=BB=E9=A2=98: [Qemu-devel] =E5=9B=9E=E5=A4=8D=EF=BC=9A dataplane b= ug: fail to start Windows VM with dataplane enable >>=20 >> Hi, Stefan: >>=20 >> Thank for your reply and patch. I have done the test for Windows 7, = Windows 2003, and fedora. >>=20 >> The patch has fixed the problem now, thanks.=20 >>=20 >> --=20 >> leiqzhang >> Sent by Sparrow >>=20 >> =E5=9C=A8 2013=E5=B9=B43=E6=9C=8827=E6=97=A5=E6=98=9F=E6=9C=9F=E4=B8=89= =EF=BC=8C23:41=EF=BC=8CStefan Hajnoczi =E5=86=99=E9=81=93=EF=BC=9A >> On Tue, Mar 26, 2013 at 11:10:35PM +0800, =E5=BC=A0=E7=A3=8A=E5=BC=BA wr= ote: >> Hi, Paolo && Stefan: >>=20 >> When I test the dataplane feature with qemu master, I find that >> Windows (Windows 7 and Windows 2003) VM will hang if dataplane is >> enabled. But if I try to start a Fedora VM, it can start normally. >>=20 >> The command I boot QEMU is: >> x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 1024 -smp 2 -drive >> file=3Dwin7.img,if=3Dnone,id=3Ddrive-virtio-disk,format=3Draw,cache=3Dno= ne,aio=3Dnative >> -device virtio-blk-pci,config-wce=3Doff,scsi=3Doff,x-data-plane=3Don,dri= ve=3Ddrive-virtio-disk,id=3Dvirtio-disk >>=20 >> I found the similar bug has reported some days ago: >> http://lists.nongnu.org/archive/html/qemu-devel/2013-03/msg02200.html >> . And a patch for this bug has already committed by Paolo at Mar 13: >> http://lists.nongnu.org/archive/html/qemu-devel/2013-03/msg02200.html >> . >>=20 >> But it cannot work under my environment. Could you give me some advise >> to debug this problem ? I can provide more information if need. >>=20 >> I sent a fix and CCed you on the patch. Please test it if you have >> time. >>=20 >> Stefan >>