Re: [PATCH net-next v2] net: stmmac: improve TSO/GSO queue selection

[Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>]

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On Aug 12, Jakub Kicinski wrote:
> On Wed, 12 Aug 2026 18:11:31 +0200 Lorenzo Bianconi wrote:
> > please drop this version, I will post v3 to fix some pending issues.
> 
> FTR Russell was trying to fix TSO in this driver too, before giving up
> (on us?). The direction he was following of clearing the TSO caps in
> ndo_features_check and letting the stack GSO instead of all the weird
> hacks this driver has seemed much more sane. But maybe I'm missing
> something TBS specific here 

Hi Jakub,

thx for the pointers. I reviewed Russell's commits and I guess we have two
options here:

- manages all the TSO/GSO checks in ndo_features_check() (stmmac_features_check())
  and disable TSO/GSO if the selected queue does not support checksum offload
  or it has TBS enabled. In this case I guess we can drop ndo_select_queue()
  callback completely (it does not make sense to me to always use queue 0 for
  TSO/GSO packets, e.g. it does not allow proper mqprio offload).
  Please note this approach would introduce some performance regressions with
  respect of the previous implementation.
- implements TSO/GSO checks in ndo_select_queue() callback
  (stmmac_select_queue()) in order to keep TSO/GSO enabled if the selected
  queue supports it and at the same time do not always use queue 0 for TSO/GSO
  packets (proper qdisc offload). Please note this is patch I am proposing.

What do you think?

Regards,
Lorenzo

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