[dpdk-stable] [PATCH 20.11] net/mlx5: fix Tx queue size created with DevX

[Luca Boccassi]

On Thu, 2021-02-18 at 20:39 +0200, Viacheslav Ovsiienko wrote:
> [ upstream commit 00984de53312b8af1bb1b6579d69a3eeda4be381 ]
> 
> The number of descriptors specified for queue creation
> implies the queue should be able to contain the specified
> amount of packets being sent. Typically one packet takes
> one queue descriptor (WQE) to be handled. If there is inline
> data option enabled one packet might require more WQEs to
> embrace the inline data and the overall queue size (the
> number of queue descriptors) should be adjusted accordingly.
> 
> In mlx5 PMD the queues can be created either via Verbs, using
> the rdma-core library or via DevX as direct kernel/firmware call.
> The rdma-core does queue size adjustment internally, depending on
> TSO and inline setting. The DevX approach missed this point.
> This caused the queue size discrepancy and performance variations.
> 
> The patch adjusts the Tx queue size for the DevX approach
> in the same as it is done in rdma-core implementation.
> 
> Fixes: 86d259cec852 ("net/mlx5: separate Tx queue object creations")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
> ---
>  drivers/net/mlx5/mlx5_devx.c | 34 +++++++++++++++++++++++++++++-----
>  1 file changed, 29 insertions(+), 5 deletions(-)

Acked-by: Luca Boccassi <luca.boccassi at microsoft.com>

Thanks, applied and pushed.

-- 
Kind regards,
Luca Boccassi