Re: [Xen-users] Xen Partition Performance

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> Thanks Matt and Mark for the correction.  What you state is true for
> paravirtualized domains (the open of the device is done in the kernel).
> HVM domains, however, open the device in user space, which means the I/O
> goes through the VFS cache.  I have been spending most of my time with HVM
> domains and incorrectly assumed that all domains have that behavior.

Good point; I spend most (well, all) time with paravirt domains, so I forgot 
about the way HVM works ;-)

When - eventually - the device models have been moved out of dom0 userspace, 
they'll go through the backend drivers and the behaviour will be the same as 
paravirt.  That doesn't look like it's going to happen for a while yet, 
though.

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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