RE: [virtio-comment] Re: [PATCH v2] virtio-net: support the virtqueue coalescing moderation

[Parav Pandit <parav@nvidia.com>]

> From: Alvaro Karsz <alvaro.karsz@solid-run.com>
> Sent: Saturday, February 11, 2023 11:14 AM
> 
> I think that I wasn't clear enough.
> 
> I'm not saying that we should not define in the spec how to handle a situation
> when a device receives both  RX_SET and VQ_SET (or a driver sends both).
> I'm saying that I don't think that the driver should handle the situation the way
> you described it:
>

> > When the driver prefers to use per virtqueue notifications coalescing, and if
> queue group (transmit or receive) level notification coalescing is enabled, driver
> SHOULD first disable device level notification coalescing.
> > Or it should be,
> >
> > Virtqueue level notifications coalescing, and device level notifications can be
> enabled together.
> > When both of them are enabled, per virtqueue notifications coalescing take
> priority over queue group level.
> 
These are the two options I proposed.
In second option missed the case of per vq followed by group level.
Which I further acked in [1] to have it as last configured.

> I think that if we want to refer to this situation in the spec, it should be
> something like:
> "A Device should use the last coalescing parameters received for a virtqueue,
> regardless of the command used to deliver the parameters."
> (just an example to make the point).

Yes, as acked in [1]. :)
We both agree on #b which you described in above example.

So things looks good. Lets wait for Heng to generate v3 covering above case.

[1] https://lists.oasis-open.org/archives/virtio-dev/202302/msg00227.html