Re: [PATCH v4 2/2] net/idpf: enable AVX2 for split queue Tx

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 9/30/2025 11:07 AM, Shaiq Wani wrote:
> In case some CPUs don't support AVX512. Enable AVX2 for them to
> get better per-core performance.
> 
> In the single queue model, the same descriptor queue is used by SW
> to post descriptors to the device and used by device to report completed
> descriptors to SW. While as the split queue model separates them into
> different queues for parallel processing and improved performance.
> 
> Signed-off-by: Shaiq Wani <shaiq.wani@intel.com>
> ---

Hi Shaiq,

> +static inline void
> +idpf_splitq_vtx_avx2(struct idpf_flex_tx_sched_desc *txdp,
> +				struct rte_mbuf **pkt, uint16_t nb_pkts, uint64_t flags)
> +{
> +	const uint64_t hi_qw_tmpl = IDPF_TX_DESC_DTYPE_FLEX_FLOW_SCHE |
> +		((uint64_t)flags);
> +
> +	/* align if needed */
> +	if (((uintptr_t)txdp & 0x1F) != 0 && nb_pkts != 0) {
> +		idpf_splitq_vtx1_avx2(txdp, *pkt, flags);
> +		txdp++, pkt++, nb_pkts--;
> +	}
> +
> +	for (; nb_pkts > 3; txdp += 4, pkt += 4, nb_pkts -= 4) {

Nitpicking, but in some other places these '4' constants are used as 
IDPF_VPMD_DESCS_PER_LOOP (or IDPF_DESCS_PER_LOOP_AVX which is 8), so it 
would be nice to reflect that in the loop header, e.g.

for (; nb_pkts >= IDPF_VPMD_DESCS_PER_LOOP;
		txdp += IDPF_VPMD_DESCS_PER_LOOP,
		pkt += IDPF_VPMD_DESCS_PER_LOOP,
		nb_pkts -= IDPF_VPMD_DESCS_PER_LOOP)

Then again, looking at other places in the same file, we do not do this 
consistently so either way would be fine.

-- 
Thanks,
Anatoly