Re: [dpdk-dev] [PATCH] net/mlx5: fix loopback for DV queue

[Thomas Monjalon <thomas@monjalon.net>]

12/05/2021 17:48, Slava Ovsiienko:
> Hi, Thomas
> 
> > How do we switch?
> 
> Historically mlx5 created Queues and other HW objects with Verbs.
> Now we are migrating ("switched") to DevX - queues are being created with DevX calls.
> If there is no E-Switch - the new DevX approach is engaged,
> for E-Switch configurations we still use Verbs.

OK this is what I thought, but it is not clear in the commit message.
We could think it is the user switching a queue :)
Please reword by comparing Verbs and DevX without saying "switch".


> From: Thomas Monjalon <thomas@monjalon.net>
> > 12/05/2021 16:51, Bing Zhao:
> > > From: Thomas Monjalon <thomas@monjalon.net>
> > > > 12/05/2021 16:36, Bing Zhao:
> > > > > When switching to the Devx interface, the kernel driver behavior
> > > > may
> > > >
> > > > What do you mean by "switching"?
> > >
> > > I mean when changing the Rxq from Verbs API to Devx API.
> > 
> > 
> > > > > be different from using Verbs. The Tx loopback cannot work
> > > > properly
> > > > > even if the Tx and Rx queues are configured with loopback
> > > > attribute.
> > > > > To support self loopback for Tx, a Verbs dummy queue pair needs to
> > > > be
> > > > > created to trigger the kernel to enable the loopback.
> > > > >
> > > > > This is only required when TIR is created for Rx and loopback is
> > > > > needed. Only CQ and QP are needed for this case, no WQ(RQ) needs
> > > > to be
> > > > > created.