[dpdk-dev] [PATCH v3 1/7] net/mlx4: remove error flows from Tx fast path

[Adrien Mazarguil]

On Mon, Oct 30, 2017 at 10:07:23AM +0000, Matan Azrad wrote:
> Move unnecessary error flows to DEBUG mode.
> 
> Signed-off-by: Matan Azrad <matan at mellanox.com>
> Acked-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>

I missed a couple of details while reviewing the original version, the first
one being mlx4_post_send()'s return value is still documented as updating
rte_errno in case of error, it's not the case anymore after this patch.

Please see below for the other one:

> ---
>  drivers/net/mlx4/mlx4_rxtx.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/mlx4/mlx4_rxtx.c b/drivers/net/mlx4/mlx4_rxtx.c
<snip>
>  /**
> @@ -510,8 +508,6 @@ struct pv {
>  	assert(max <= elts_n);
>  	/* Always leave one free entry in the ring. */
>  	--max;
> -	if (max == 0)
> -		return 0;
>  	if (max > pkts_n)
>  		max = pkts_n;
>  	for (i = 0; (i != max); ++i) {

While minor, this change has nothing to do with this patch, right?

I think it can slightly degrade an application performance as it removes the
guarantee that subsequent code only needs to be run if there is at least one
packet to process in case the TX ring is constantly full (SW faster than
HW).

Can you remove it?

-- 
Adrien Mazarguil
6WIND