Re: [dpdk-dev] [PATCH v2 2/3] vdpa/mlx5: optimize completion queue poll

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 6/25/20 3:30 PM, Matan Azrad wrote:
> The vDPA driver uses a CQ in order to know when traffic works were
> completed by the HW.
> 
> Each traffic burst completion adds a CQE to the CQ.
> 
> When the vDPA driver detects CQEs in the CQ, it triggers the guest
> notification for the corresponding queue and consumes all of them.
> 
> There is collapse feature in the HW that configures the HW to write all the
> CQEs in the first entry of the CQ.
> 
> Using this feature, the vDPA driver can read only the first CQE,
> validate that the completion counter inside the CQE was changed and if
> so, to notify the guest.
> 
> Use CQ collapse feature in order to improve the poll utilization.
> 
> Signed-off-by: Matan Azrad <matan@mellanox.com>
> ---
>  drivers/vdpa/mlx5/mlx5_vdpa_event.c | 73 ++++++++++++++++++++-----------------
>  1 file changed, 40 insertions(+), 33 deletions(-)
> 
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime