Symmetric RSS Hashing support in DPDK

[Balakrishnan K]

Hi Stephen,
  Thanks for the response . I will below option and come back if any help required.

Regards,
Bala

-----Original Message-----
From: Stephen Hemminger <stephen at networkplumber.org>
Sent: Wednesday, March 6, 2024 8:34 PM
To: Balakrishnan K <Balakrishnan.K1 at tatacommunications.com>
Cc: users at dpdk.org
Subject: Re: Symmetric RSS Hashing support in DPDK

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On Wed, 6 Mar 2024 07:28:40 +0000
Balakrishnan K <Balakrishnan.K1 at tatacommunications.com> wrote:

> Hello,
>    Our application needs symmetric hashing to handle the reverse
> traffic on the same core, also to Improve performance by distributing the traffic across core.
> Tried using rss config as below .
> action_rss_tcp.types = ETH_RSS_NONFRAG_IPV4_TCP | ETH_RSS_L3_SRC_ONLY|
> ETH_RSS_L3_DST_ONLY | ETH_RSS_L4_SRC_ONLY | ETH_RSS_L4_DST_ONLY; but could not get desired result.
> Is there any options or API available to enable symmetric RSS hashing .
> We are using dpdk 20.11 and intel NIC X710 10GbE .
>
> Regards,
> Bala

With XL710 there are two choices:
        1. Set RSS hash function to RTE_ETH_HASH_SYMMETRIC_TOEPLITZ in
           the rte_eth_rss_conf passed in during configure
        2. Use default (non symmetric TOEPLITZ) but pass in a rss_key that
           has duplicated bits in the right place. Like:

0x6d5a 0x6d5a 0x6d5a 0x6d5a
0x6d5a 0x6d5a 0x6d5a 0x6d5a
0x6d5a 0x6d5a 0x6d5a 0x6d5a
0x6d5a 0x6d5a 0x6d5a 0x6d5a
0x6d5a 0x6d5a 0x6d5a 0x6d5a

        https://www.ndsl.kaist.edu/~kyoungsoo/papers/TR-symRSS.pdf