On 06/19/2009 01:15 PM, Paolo Bonzini wrote:
From: Paolo Bonzini<[email protected]>
KVM's optimization of guest port 80 accesses was removed last May 11
in commit 99f85a. However, this probably has speed penalties. I don't
have a machine to test but the equivalent VMX patch (fdef3ad) reported
a speedup of 3-5%, and on the Xen mailing list it was mentioned that on
Xen passing port 80 through had positive effects on startup speed.
We can enable passthrough to the same port the host kernel uses instead.
Since we don't tell the guest to use 0xed, this won't help. If we can
tell the guest, we can just tell it not to use any port at all, since
this is a virtualized environment and there's no buggy hardware to please.
We could speed it up by trapping and emulating the port write in the
kernel instead of letting userspace handle it (should be faster than
passthrough on newer hosts). I'd like to make is configurable from
userspace though, the kernel has no business trapping random ports.
--
error compiling committee.c: too many arguments to function
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