RE: [PATCH v3] net/iavf: revert fix VLAN insertion

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Yiding Zhou <yidingx.zhou@intel.com>
> Sent: Friday, November 4, 2022 2:10 PM
> To: dev@dpdk.org
> Cc: ktraynor@redhat.com; Yang, Qiming <qiming.yang@intel.com>; Zhou,
> YidingX <yidingx.zhou@intel.com>
> Subject: [PATCH v3] net/iavf: revert fix VLAN insertion
> 
> The vector Tx path does not support VLAN insertion via the L2TAG2 field, but
> the scalar path supports. The previous commit was to force to select scalar
> path as soon as kernel driver requests to use L2TAG2.

In which situation, that kernel driver will request to use L2TAG2?
> 
> That logic is incorrect. Because other case like VLAN offloading not required
> but scalar path selected would have a significant performance drop .
> Therefore the following commit needs to revert.

What will happen, if kernel driver request to use L2TAG2, but still vector path is selected?

> 
> commit 0d58caa7d6d1 ("net/iavf: fix VLAN insertion")
> 
> After this commit reverted, the user can select scalar path with the
> parameter '--force-max-simd-bitwidth' if necessary.
> 
> Fixes: 0d58caa7d6d1 ("net/iavf: fix VLAN insertion")
> 
> Signed-off-by: Yiding Zhou <yidingx.zhou@intel.com>
> ---
> v3: rebase and change commit log
> ---
>  drivers/net/iavf/iavf_rxtx_vec_common.h | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/drivers/net/iavf/iavf_rxtx_vec_common.h
> b/drivers/net/iavf/iavf_rxtx_vec_common.h
> index 4ab22c6b2b..a59cb2ceee 100644
> --- a/drivers/net/iavf/iavf_rxtx_vec_common.h
> +++ b/drivers/net/iavf/iavf_rxtx_vec_common.h
> @@ -253,9 +253,6 @@ iavf_tx_vec_queue_default(struct iavf_tx_queue *txq)
>  	if (txq->offloads & IAVF_TX_NO_VECTOR_FLAGS)
>  		return -1;
> 
> -	if (txq->vlan_flag == IAVF_TX_FLAGS_VLAN_TAG_LOC_L2TAG2)
> -		return -1;
> -
>  	if (txq->offloads & IAVF_TX_VECTOR_OFFLOAD)
>  		return IAVF_VECTOR_OFFLOAD_PATH;
> 
> --
> 2.34.1