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Re: [Xen-users] Does a PAE domU work with non-PAE dom0?

> Just out of interest, with a 64-bit hypervisor, which of the HVM options
> (32, 32p, 64) will give the lowest overhead? Or are they going to be
> more the same than they are different?

Hmmm.  I suspect they're more the same than different...  It *might* be that 
one or the other reduces the overhead of maintaining shadow pagetables.  But 
I wouldn't be surprised if they came out fairly similar in terms of overhead.

Of course, if you use a 64-bit guest then the guest applications get the 
advantage or a larger virtual memory space and of extra registers, so they 
may benefit in performance because of that.

Amusingly for PV guests, I strongly suspect the overhead is lower when running 
32-bit PAE guests on 64-bit Xen than when running native 64-bit guests.  That 
may well extend to dom0 too.  Also, glibc's negative segment offset tricks 
would work for 32-bit guests under 64-bit Xen at full performance...  Crazy 
stuff ;-)


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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