On Thu, 22 Jun 2023 09:22:36 -0700 longli@xxxxxxxxxxxxxxxxx wrote:
> It's inefficient to ring the doorbell page every time a WQE is posted to
> the received queue.
>
> Move the code for ringing doorbell page to where after we have posted all
> WQEs to the receive queue during a callback from napi_poll().
>
> Tests showed no regression in network latency benchmarks.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
If this is supposed to be a fix, you need to clearly explain what the
performance loss was, so that backporters can make an informed decision.
> drivers/net/ethernet/microsoft/mana/gdma_main.c | 5 ++++-
> drivers/net/ethernet/microsoft/mana/mana_en.c | 10 ++++++++--
> 2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index 8f3f78b68592..ef11d09a3655 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> @@ -300,8 +300,11 @@ static void mana_gd_ring_doorbell(struct gdma_context *gc, u32 db_index,
>
> void mana_gd_wq_ring_doorbell(struct gdma_context *gc, struct gdma_queue *queue)
> {
> + /* BNIC Spec specifies that client should set 0 for rq.wqe_cnt
> + * This value is not used in sq
> + */
> mana_gd_ring_doorbell(gc, queue->gdma_dev->doorbell, queue->type,
> - queue->id, queue->head * GDMA_WQE_BU_SIZE, 1);
> + queue->id, queue->head * GDMA_WQE_BU_SIZE, 0);
> }
This change needs to be explained in the commit message, or should be
a separate patch.
--
pw-bot: cr
