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

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

On Wed, Feb 08, 2023 at 10:23:00PM +0000, Parav Pandit wrote:
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Wednesday, February 8, 2023 5:16 PM
> > > > Not having this feature/command even complicates things now that we
> > > > are talking about removing the RX and TX from the per vq command,
> > > > how do you change parameters to all TX queues? to all RX queues?
> > > > we'll need 2 special indexes, so we now need le32 to hold the queue index.
> > > No need for special index.
> > > How does a driver disable all queues or reset all queues? -> One by one.
> > > So if user want to change for all TXQ, sw can do it one by one by iterating TXQ
> > vqns.
> > 
> > I think we can split this effort in two parts:
> > 
> > 1. add a new command and feature bit
> > 2. drop the old command
> > 
> > 
> > Looks like there's consensus on 1?  And it looks like Alvaro wants to work on 1
> > but not 2. Once that is in Parav can work on 2 if he wants to.
> 
> 3. rename the current one if there is no sw driver that used it.

That's probably the worst of all options, silently changing behaviour.

> May be lets wait for Alvaro's answer if there is any sw that used.
> 
> Doing #3 would be the simplest for all devices and sw to implement and consume respectively.
> 
> I can work with Alvaro to have 1 and 2 as part of same series as two patches, so that we don't have to re-discuss this again.
> Without that 
> a. negotiating two bits at same time is hard.
> b. Wording #1 also need to mention about what happens when global is also negotiated and device is in partial mode.

There's no mode, partial or otherwise, in either Alvaro's or my
proposal.

-- 
MST