[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] why do I get bad disk write performance in the kernel 3.1?
On Wed, Nov 09, 2011 at 02:52:59PM -0200, Roberto Scudeller wrote: > Konrad, > > Thanks for help. OK, so looks like you are using qdisk. Can you try creating an LVM and blasting the image onto that? And obviously then using 'phy:/dev/vg_guest/...' ? You could also try the 'file:/local-disk' which will setup a loopback device and use that. Try that as well. > > My windows.cfg is: > name='benchCM-windows-2003-64b-std-test' > kernel='/usr/lib/xen/boot/hvmloader' > builder='hvm' > memory=512 > vcpus=2 > pae=1 > acpi=1 > apic=1 > disk=[ 'tap2:aio:/local-disk/benchCM-windows-2003-64b-std/xvda,xvda,w' ] > device_model='/usr/lib/xen/bin/qemu-dm' > boot='c' > sdl=0 > vnc=1 > vncunused=1 > vnclisten='0.0.0.0' > vncpasswd='' > stdvga=0 > extra='' > on_reboot='restart' > on_shutdown='destroy' > ramdisk='' > image_name='' > on_crash='destroy' > bootloader='' > root='' > platform='xen' > network_mode='tap' > usb = 1 > usbdevice = 'tablet' > > The xvda disk is a raw disk, created with dd. > I use the windows.cfg in both kernel. > > > > 2011/11/9 Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > > On Wed, Nov 09, 2011 at 12:58:27PM -0200, Roberto Scudeller wrote: > > > Hi all, > > > > > > I'm testing the new kernel 3.1 from kernel.org, and xen 4.1.2-rc1-pre. > > > I execute a CrystalMark IO Benchmark, in windows 2003 VM with gplpv > > > drivers, and receive an amazing result for reading, but the write numbers > > > are very disappointing. > > > > > > I run the VM in local disk, and receive these numbers: > > > Seq read: 244 MB/s > > > 512K read: 239 MB/s > > > 4K read: 27 MB/s > > > 4K QD 32: 90 MB/s > > > > > > Seq write: 20 MB/s > > > 512K: 20 MB/s > > > 4K: 8 MB/s > > > 4K QD 32: 12MB/s > > > > > > In older kernel, 2.6.32.x: > > > Seq read: 189 MB/s > > > 512K read: 169 MB/s > > > 4K read: 11 MB/s > > > 4K QD 32: 34 MB/s > > > > > > Seq write: 177 MB/s > > > 512K: 166 MB/s > > > 4K: 12 MB/s > > > 4K QD 32: 36 MB/s > > > > > > Could anyone help me. Why is the new kernel faster in reading, but too > > slow > > > writing ? > > > > It would help if you gave an idea of what the guest configuration is and > > what is the backend. It might be that the backend you are using in 3.1 is > > QEMU qdisk, not xen-blkback. > > > > > > -- > Roberto Scudeller _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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