Hmm, so we have:

> Solaris HVM DomU at SNV87 Dom0 (all 64-bit)
> # elasped time    306.42171

Hmm, slow.

> Test has been run on SNV87 HVM DomU at Xen 3.2.1 CentOS 5.1 Dom0 (all 64-bit)
> #  elasped time  40.26895

Ok.

> Workaround was applied to SNV87 HVM DomU at Xen 3.2.1 CentOS 5.1 Dom0 (all 
> 64-bit)
> # elasped time 35.59440

The workaround improves run time, but only by ~ 10%.

> Test has been run on SNV87 PV DomU at Xen 3.2.1 CentOS 5.1 Dom0 (all 64-bit)
> # elasped time 10.34040

Yep, for a HVM domain the hypervisor must fully emulate
the MMU using shadow page tables; with a PV domain this
isn't necessary and is much faster.

> Test has been run on SNV87 PV DomU at SNV87 Dom0 (all 64-bit)
> # elasped time 12.51547

Hmm, this test was run on OpenSolaris' xVM / Xen 3.1.2 hypervisor...

I don't expect that the SNV87 Dom0 kernel vs CentOS 5.1 Dom0 kernel
makes a difference, so I think this might be an indication that Xen 3.2.1 has
improved PV MMU support over Xen 3.1.2...

And for a Solaris HVM domU, the HVM MMU performance increase appears
to be even more dramatic between Xen 3.1.2 and Xen 3.2.1...
 
 
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