Re: [PATCHv2] vhost-net: utilize PUBLISH_USED_IDX feature

From: Avi Kivity
Date: Wed May 19 2010 - 12:16:13 EST

On 05/18/2010 08:47 PM, Avi Kivity wrote:
On 05/18/2010 05:21 AM, Michael S. Tsirkin wrote:
With PUBLISH_USED_IDX, guest tells us which used entries
it has consumed. This can be used to reduce the number
of interrupts: after we write a used entry, if the guest has not yet
consumed the previous entry, or if the guest has already consumed the
new entry, we do not need to interrupt.
This imporves bandwidth by 30% under some workflows.

Seems to be missing the cacheline alignment.

Rusty's clarification did not satisfy me, I think it's needed.

Oh, and this should definitely follow the patch to the virtio spec, not precede it.

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

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