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

[Parav Pandit <parav@nvidia.com>]

> From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> Sent: Tuesday, February 7, 2023 6:50 AM
> 
> On Tue, 7 Feb 2023 13:25:13 +0200, Alvaro Karsz <alvaro.karsz@solid-run.com>
> wrote:
> > Hi Heng,
> >
> > > Currently, the coalescing profile is directly applied to all queues.
> > > This patch supports configuring the parameters for a specified queue.
> > >
> > > When the traffic between queues is unbalanced, for example, one
> > > queue is busy and another queue is idle, then it will be very useful
> > > to control coalescing parameters at the queue granularity.
> > >
> > > Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
> > > Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > > ---
> > >  content.tex | 49 ++++++++++++++++++++++++++++++++++++++++++-------
> > >  1 file changed, 42 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/content.tex b/content.tex index e863709..049c0e4 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -3084,6 +3084,9 @@ \subsection{Feature bits}\label{sec:Device
> > > Types / Network Device / Feature bits
> \item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control
> > >      channel.
> > >
> > > +\item[VIRTIO_NET_F_PERQUEUE_NOTF_COAL(52)] Device supports per-
> queue
> > > +       notifications coalescing.
> > > +
> >
> > Since this feature allows us to change the coalescing parameters for
> > all the queues when rx/tx_qid = 0xFFFF, and since version 1.3 wasn't
> > released yet, maybe the "per-vq" functionality can be added to
> > VIRTIO_NET_F_NOTF_COAL instead of adding a new feature?
> 
> 
> According to my understanding, all the features of voting are formal. It can be
> used by the manufacturer.
> 
> Of course, as far as I know, no manufacturer has used this feature for the time
> being. But I think we should add a new feature.
> 
> Or other people have other ideas.

I believe we should treat it as fix and avoid a new feature bit as spec is not released, and it is very recent change.