Re: [Qemu-devel] [RFC] Next gen kvm api

From: Avi Kivity
Date: Tue Feb 07 2012 - 07:04:04 EST

On 02/06/2012 09:11 PM, Anthony Liguori wrote:

I'm not so sure. ioeventfds and a future mmio-over-socketpair have to put the kthread to sleep while it waits for the other end to process it. This is effectively equivalent to a heavy weight exit. The difference in cost is dropping to userspace which is really neglible these days (< 100 cycles).

On what machine did you measure these wonderful numbers?

But I agree a heavyweight exit is probably faster than a double context switch on a remote core.

I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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