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

[Heng Qi <hengqi@linux.alibaba.com>]

On Sat, Feb 11, 2023 at 06:13:55PM +0200, Alvaro Karsz wrote:
> 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.
> 
> This implies that we have 2 modes and have priorities.
> 
> 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."

Your suggestion is good, the per-device command and the per-queue command need some examples and behavior definitions,
I will add them to avoid some misunderstandings.

Thanks.

> (just an example to make the point).