Re: VM performance issue in KVM guests.

From: Avi Kivity
Date: Sat Apr 17 2010 - 15:05:09 EST


On 04/15/2010 04:33 PM, Peter Zijlstra wrote:
On Thu, 2010-04-15 at 11:18 +0300, Avi Kivity wrote:
Certainly that has even greater potential for Linux guests. Note that
we spin on mutexes now, so we need to prevent preemption while the lock
owner is running.
either that, or disable spinning on (para) virt kernels.

What would you do instead?

Note we can't disable spinning on Windows or pre 2.6.36 kernels.

Para virt
kernels could possibly extend the thing by also checking to see if the
owner's vcpu is running.

Certainly that's worth doing.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

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