Re: [virtio-comment] [PATCH] virtio-net: support per-queue coalescing moderation

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Feb 08, 2023 at 07:30:34PM +0800, Heng Qi wrote:
> > I see two options.
> > 1. Just have per VQ params. Software has the full knowledge of in which it is operating, and state remains at software level.
> > This effectively achieves both the mode.
> > 
> > 2. Have a mode cmd,
> > Mode = (a) per device or (b) per VQ (c) disable
> > After the mode is set, driver can set per device or per VQ.
> 
> I find this more clear.
> 
> Thanks.
> 

Rereading this I think I misunderstood the proposal.
Now we are burning memory on maintaining mode, and this information is
duplicated.

I'd say let's just add a new command COAL_QUEUE_SET with vqn
as parameter. Existing commands are simply defined as
a shortcut to running COAL_QUEUE_SET on all tx/rx queues
respectively.

Latest command dictates the parameters. To disable just set everything
to 0 (btw we should make this explicit in the spec, but it can be
guessed from:
Upon reset, a device MUST initialize all coalescing parameters to 0.
)

-- 
MST