Re: [patch net-next] virtio_net: add support for Byte Queue Limits

2024-06-10 Thread Michael S. Tsirkin
On Fri, Jun 07, 2024 at 01:30:34PM +0200, Jiri Pirko wrote:
> Fri, Jun 07, 2024 at 12:23:37PM CEST, m...@redhat.com wrote:
> >On Fri, Jun 07, 2024 at 11:57:37AM +0200, Jiri Pirko wrote:
> >> >True. Personally, I would like to just drop orphan mode. But I'm not
> >> >sure others are happy with this.
> >> 
> >> How about to do it other way around. I will take a stab at sending patch
> >> removing it. If anyone is against and has solid data to prove orphan
> >> mode is needed, let them provide those.
> >
> >Break it with no warning and see if anyone complains?
> 
> This is now what I suggested at all.
> 
> >No, this is not how we handle userspace compatibility, normally.
> 
> Sure.
> 
> Again:
> 
> I would send orphan removal patch containing:
> 1) no module options removal. Warn if someone sets it up
> 2) module option to disable napi is ignored
> 3) orphan mode is removed from code
> 
> There is no breakage. Only, hypotetically performance downgrade in some
> hypotetical usecase nobody knows of.

Performance is why people use virtio. It's as much a breakage as any
other bug. The main difference is, with other types of breakage, they
are typically binary and we can not tolerate them at all.  A tiny,
negligeable performance regression might be tolarable if it brings
other benefits. I very much doubt avoiding interrupts is
negligeable though. And making code simpler isn't a big benefit,
users do not care.

> My point was, if someone presents
> solid data to prove orphan is needed during the patch review, let's toss
> out the patch.
> 
> Makes sense?

It's not hypothetical - if anything, it's hypothetical that performance
does not regress.  And we just got a report from users that see a
regression without.  So, not really.

> 
> >
> >-- 
> >MST
> >




Re: [PATCH net-next] virtio_net: Add TX stop and wake counters

2024-06-10 Thread Jakub Kicinski
On Sat, 8 Jun 2024 08:41:44 +0800 Jason Xing wrote:
> > > Sorry to revive this thread. I wonder why not use this patch like mlnx 
> > > driver
> > > does instead of adding statistics into the yaml file? Are we gradually 
> > > using or
> > > adding more fields into the yaml file to replace the 'ethtool -S' command?
> > >  
> >
> > It's trivial to have the stats in ethtool as well. But I noticed
> > the stats series intentionally removed some stats from ethtool. So
> > I didn't put it both places.  
> 
> Thank you for the reply. I thought there was some particular reason
> :-)

Yes, we don't want duplication. We have a long standing (and
documented) policy against duplicating normal stats in custom stat
APIs, otherwise vendors pile everything into the custom stats.



Re: [PATCH net-next] virtio_net: Add TX stop and wake counters

2024-06-10 Thread Jason Xing
On Tue, Jun 11, 2024 at 1:57 AM Jakub Kicinski  wrote:
>
> On Sat, 8 Jun 2024 08:41:44 +0800 Jason Xing wrote:
> > > > Sorry to revive this thread. I wonder why not use this patch like mlnx 
> > > > driver
> > > > does instead of adding statistics into the yaml file? Are we gradually 
> > > > using or
> > > > adding more fields into the yaml file to replace the 'ethtool -S' 
> > > > command?
> > > >
> > >
> > > It's trivial to have the stats in ethtool as well. But I noticed
> > > the stats series intentionally removed some stats from ethtool. So
> > > I didn't put it both places.
> >
> > Thank you for the reply. I thought there was some particular reason
> > :-)
>
> Yes, we don't want duplication. We have a long standing (and
> documented) policy against duplicating normal stats in custom stat
> APIs, otherwise vendors pile everything into the custom stats.

Thanks, Jakub. I see :)