Virtualization - Sep 2022 - [PATCH v5 2/2] virtio-net: use mtu size as buffer length for big packets

> From: Michael S. Tsirkin <mst at redhat.com>
> Sent: Wednesday, September 7, 2022 3:24 PM
> 
> On Wed, Sep 07, 2022 at 07:18:06PM +0000, Parav Pandit wrote:
> >
> > > From: Michael S. Tsirkin <mst at redhat.com>
> > > Sent: Wednesday, September 7, 2022 3:12 PM
> >
> > > > Because of shallow queue of 16 entries deep.
> > >
> > > but why is the queue just 16 entries?
> > I explained the calculation in [1] about 16 entries.
> >
> > [1]
> >
> https://lore.kernel.org/netdev/PH0PR12MB54812EC7F4711C1EA4CAA119DC
> 419@
> > PH0PR12MB5481.namprd12.prod.outlook.com/
> >
> > > does the device not support indirect?
> > >
> > Yes, indirect feature bit is disabled on the device.
> 
> OK that explains it.
So can we proceed with v6 to contain 
(a) updated commit message and
(b) function name change you suggested to drop _fields suffix?

On Wed, Sep 07, 2022 at 07:27:16PM +0000, Parav Pandit
wrote:
> 
> > From: Michael S. Tsirkin <mst at redhat.com>
> > Sent: Wednesday, September 7, 2022 3:24 PM
> > 
> > On Wed, Sep 07, 2022 at 07:18:06PM +0000, Parav Pandit wrote:
> > >
> > > > From: Michael S. Tsirkin <mst at redhat.com>
> > > > Sent: Wednesday, September 7, 2022 3:12 PM
> > >
> > > > > Because of shallow queue of 16 entries deep.
> > > >
> > > > but why is the queue just 16 entries?
> > > I explained the calculation in [1] about 16 entries.
> > >
> > > [1]
> > >
> > https://lore.kernel.org/netdev/PH0PR12MB54812EC7F4711C1EA4CAA119DC
> > 419@
> > > PH0PR12MB5481.namprd12.prod.outlook.com/
> > >
> > > > does the device not support indirect?
> > > >
> > > Yes, indirect feature bit is disabled on the device.
> > 
> > OK that explains it.
> 
> So can we proceed with v6 to contain 
> (a) updated commit message and
> (b) function name change you suggested to drop _fields suffix?
(c) replace mtu = 0 with sensibly not calling the function
when mtu is unknown.


And I'd like commit log to include results of perf testing
- with indirect feature on
- with mtu feature off
just to make sure nothing breaks.

-- 
MST