Re: [Xen-devel] why do I get bad disk write performance in the k

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.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread]

Current Thread

[Next in Thread>

Previous by Date:

[Xen-devel] Re: [PATCH 1/3] cpuidle: If disable_cpuidle() is called, set pm_idle to default_idle., Konrad Rzeszutek Wilk

Next by Date:

[Xen-devel] [PATCH 3 of 6] amd iommu: Simplify IVHD device flag handling, Wei Wang

Previous by Thread:

[Xen-devel] why do I get bad disk write performance in the kernel 3.1?, Roberto Scudeller

Next by Thread:

Re: [Xen-devel] why do I get bad disk write performance in the kernel 3.1?, Roberto Scudeller

Indexes:

[Date] [Thread] [Top] [All Lists]