Re: [PATCH v5 2/2] common/idpf: enable AVX2 for single queue Tx

[Bruce Richardson <bruce.richardson@intel.com>]

On Mon, Feb 03, 2025 at 01:25:08PM +0530, Shaiq Wani wrote:
> In case some CPUs don't support AVX512. Enable AVX2 for them to
> get better per-core performance.
> 
> The single queue model processes all packets in order while
> the split queue model separates packet data and metadata into
> different queues for parallel processing and improved performance.
> 
> Signed-off-by: Shaiq Wani <shaiq.wani@intel.com>
> ---
>  doc/guides/nics/idpf.rst                    |   8 +-
>  doc/guides/rel_notes/release_25_03.rst      |   7 +
>  drivers/common/idpf/idpf_common_device.h    |   1 +
>  drivers/common/idpf/idpf_common_rxtx.h      |   4 +
>  drivers/common/idpf/idpf_common_rxtx_avx2.c | 224 ++++++++++++++++++++
>  drivers/common/idpf/version.map             |   1 +
>  drivers/net/intel/idpf/idpf_rxtx.c          |  13 ++
>  7 files changed, 255 insertions(+), 3 deletions(-)
> 
> diff --git a/doc/guides/nics/idpf.rst b/doc/guides/nics/idpf.rst
> index 0370989a07..90b651d193 100644
> --- a/doc/guides/nics/idpf.rst
> +++ b/doc/guides/nics/idpf.rst

<snip>

> +static __rte_always_inline int
> +idpf_singleq_tx_free_bufs_vec(struct idpf_tx_queue *txq)
> +{
> +	struct idpf_tx_entry *txep;
> +	uint32_t n;
> +	uint32_t i;
> +	int nb_free = 0;
> +	struct rte_mbuf *m, *free[txq->rs_thresh];
> +

Use of these variable-length arrays is no longer allowed in DPDK. The
AVX512 equivalent of this code uses alloca, so will update this on apply to
match that.

/Bruce