-----Original Message-----
From: Min Hu (Connor) <redacted>
Sent: Wednesday, June 30, 2021 7:22 PM
To: Yigit, Ferruh <redacted>; dev@dpdk.org; Thomas Monjalon
[off-list ref]; Andrew Rybchenko
[off-list ref]
Cc: Xing, Beilei <redacted>; Matan Azrad
[off-list ref]; shahafs@nvidia.com; viacheslavo@nvidia.com
Subject: Re: Question about 'rxm->hash.rss' and 'mb->hash.fdir'

Hi, Beilei, Matan, Shahaf, Viacheslav,

	how about your opinion?

Agree with Ferruh.

在 2021/6/30 17:34, Ferruh Yigit 写道:

quoted

On 6/30/2021 3:45 AM, Min Hu (Connor) wrote:

quoted

Hi, all
     one question about 'rxm->hash.rss' and 'mb->hash.fdir'.

     In Rx recv packets function,
     'rxm->hash.rss' will report rss hash result from Rx desc.
     'rxm->hash.fdir' will report filter identifier from Rx desc.

     But function implementation differs from some PMDs. for example:
     i40e, MLX5 report the two at the same time if pkt_flags is set,like:
******************************************
         if (pkt_flags & PKT_RX_RSS_HASH) {
             rxm->hash.rss =
rte_le_to_cpu_32(rxd.wb.qword0.hi_dword.rss);
         }
         if (pkt_flags & PKT_RX_FDIR) {
             mb->hash.fdir.hi =
         rte_le_to_cpu_32(rxdp->wb.qword3.hi_dword.fd_id);
         }
********************************************

     While, ixgbe only report one of the two. like:
******************************************
         if (likely(pkt_flags & PKT_RX_RSS_HASH))
             mb->hash.rss = rte_le_to_cpu_32(
                 rxdp[j].wb.lower.hi_dword.rss);
         else if (pkt_flags & PKT_RX_FDIR) {
             mb->hash.fdir.hash = rte_le_to_cpu_16(
                 rxdp[j].wb.lower.hi_dword.csum_ip.csum) &
                 IXGBE_ATR_HASH_MASK;
             mb->hash.fdir.id = rte_le_to_cpu_16(
                 rxdp[j].wb.lower.hi_dword.csum_ip.ip_id);
         }
********************************************
     So, what is application scenario for 'rxm->hash.rss' and
'mb->hash.fdir', that is, why the two should be reported? How about
reporting the two at the same time?
     Thanks for  your reply.

Hi Connor,

mbuf->hash is union, so it is not possible to set both 'hash.rss' & 'hash.fdir'.

I assume for i40e & mlx5 case 'pkt_flags' indicate which one is valid
and only one is set in practice. Cc'ed driver mainteriners for more comment.

Thanks Ferruh,
	another question, why does user need this information:  rxm-

quoted

hash.rss or mb->hash.fdir.hi ? what is the function?

quoted

.