Re: [dpdk-stable] [DPDK] net/ice: fix txq mbuf release mode

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/25/2021 10:26 AM, Alvin Zhang wrote:
> In some cases, it seems that the txq mbuf vector release mode
> is enabled first, and then it is confirmed that the conditions
> for using the vector mode are not met.
> 

Hi Alvin,

As far as I understand the impact is failure in the Tx vector patch selection,
can you please update the patch title to reflect it?

Also can you please describe a little more what is "txq mbuf vector release
mode" and what is the root cause for it to be enabled first?

> This patch puts the txq vector mode startup process after the
> condition detection.

What is "txq vector mode startup process"?

> 
> Fixes: 28f9002ab67f ("net/ice: add Tx AVX512 offload path")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
> ---
>  drivers/net/ice/ice_rxtx.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c
> index 92fbbc1..49abcb2 100644
> --- a/drivers/net/ice/ice_rxtx.c
> +++ b/drivers/net/ice/ice_rxtx.c
> @@ -3303,13 +3303,6 @@
>  		if (tx_check_ret >= 0 &&
>  		    rte_vect_get_max_simd_bitwidth() >= RTE_VECT_SIMD_128) {
>  			ad->tx_vec_allowed = true;
> -			for (i = 0; i < dev->data->nb_tx_queues; i++) {
> -				txq = dev->data->tx_queues[i];
> -				if (txq && ice_txq_vec_setup(txq)) {
> -					ad->tx_vec_allowed = false;
> -					break;
> -				}
> -			}
>  
>  			if (rte_vect_get_max_simd_bitwidth() >= RTE_VECT_SIMD_512 &&
>  			rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX512F) == 1 &&
> @@ -3329,6 +3322,15 @@
>  			if (!use_avx512 && tx_check_ret == ICE_VECTOR_OFFLOAD_PATH)
>  				ad->tx_vec_allowed = false;
>  
> +			if (ad->tx_vec_allowed) {
> +				for (i = 0; i < dev->data->nb_tx_queues; i++) {
> +					txq = dev->data->tx_queues[i];
> +					if (txq && ice_txq_vec_setup(txq)) {
> +						ad->tx_vec_allowed = false;
> +						break;
> +					}
> +				}
> +			}
>  		} else {
>  			ad->tx_vec_allowed = false;
>  		}
>