[PATCH] app/testpmd: warn on shared rxq switch mismatch

[Dariusz Sosnowski]

> -----Original Message-----
> From: Stephen Hemminger <stephen at networkplumber.org>
> Sent: Monday, March 23, 2026 5:17 PM
> To: a.schollmeyer at syseleven.de
> Cc: Aman Singh <aman.deep.singh at intel.com>; dev at dpdk.org
> Subject: Re: [PATCH] app/testpmd: warn on shared rxq switch mismatch
> 
> On Tue, 25 Nov 2025 11:22:07 +0100
> a.schollmeyer at syseleven.de wrote:
> 
> > From: Adrian Schollmeyer <a.schollmeyer at syseleven.de>
> >
> > Shared Rx queues do not work with every combination of ports. Besides
> > requiring the corresponding device capability, shared Rx queues also
> > require all ports of one share group and queue ID have the same switch
> > domain and Rx domain. When these fields do not match, shared Rx queues
> > are not properly set up and queue sharing may fail silently. This can
> > happen even in some less intuitive cases like multiple VFs of one
> > physical NIC.

Adrian: Could you please elaborate what kind of issues have you faced with shared queue configuration?

> >
> > To make debugging issues with shared Rx queue configuration easier,
> > this commit introduces simple checks and warning messages for all
> > members of a share_group and share_qid to warn whenever there is a
> > mismatch in the switch and Rx domain.
> >
> > Signed-off-by: Adrian Schollmeyer <a.schollmeyer at syseleven.de>
> > ---
> 
> Why is this not handled at ethdev or device level?

Are you referring to share group index logic?

Based on current implementation in ethdev and mlx5 PMD,
assuring that share group indexes are unique is not needed.
Share group index is not required to be globally unique since
sharing works only within the same switch and Rx domain [1].

> 
> Testpmd is just a test program. Real applications might make same mistake.

Best regards,
Dariusz Sosnowski

---

[1]: https://inbox.dpdk.org/dev/yotjxacqrodttraqrr3r6ftut4cty66g6cjnr5ughswtatapgh@gqqkftskp3qq/