Alexander Graf wrote:
There's only a limited potential here (a factor of three, reducing 6
exits to 2, less the emulation overhead). There's a lot more to be
gained from nested npt, since you'll avoid most of the original exits
in the first place.
I think the reversed is the case. Look at those numbers (w2k8 bootup):
http://pastebin.ca/1423596
The only thing nested NPT would achieve is a reduction of #NPF exits.
But they are absolutely in the minority today already. Normal #PF's do
get directly passed to the guest already.
#NPF exits are caused when guest/host mappings change, which they don't,
or by mmio (which happens both for guest and nguest).
I don't understand how you can pass #PFs directly to the guest. Surely
the guest has enabled pagefault interception, and you need to set up its
vmcb?
Of course, this all depends on the workload. For kernbench style
benchmarks nested NPT probably gives you a bigger win, but anything
doing IO is slowed down way more than it has to now.
What is causing 17K pio exits/sec? What port numbers?
--
error compiling committee.c: too many arguments to function
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