Re: [Xen-devel] File System Performance - 10x slower

Nauzad Sadry
2005-01-11T21:51:39Z

Thanks guys for your help

I will inspect the driver configuration in my system & get back.

On using hdparm is found out that DMA is disabled by default in Xen
(it was enabled on baseline) & I probably need to rebulid the kernel
with this option turned on.

If there are any other ways to turn on this option, please let me know

Thanks

Nauzad

On Tue, 11 Jan 2005 19:11:53 -0000, Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
wrote:
>
> Check that the domain 0 kernel you are using has the appropriate drivers
> for your hardware. It''s probably using PIO or something daft.
>
> > I ask since it should be almost *impossible* to get anything more
> > than a very small % slowdown on disk I/O unless things are very
> > broken -- most of our benchmarks to date show 0% slowdown (and
> > in some cases involving domU, a speedup due to additional buffering).
>
> Ian