Re: Symmetric RSS Hashing support in DPDK

["Shaul Hamoi (shamoi)" <shamoi@cisco.com>]

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Hi,


I am looking to determine the target queue for a flow in advance
I’m using dpdk-rss-flows.py to calculate the Toeplitz hash with I40E key.

However, If I use the script as is, I don’t obtain the correct queue because the hash calculation isn’t symmetric.
I have attempted to XOR the source and destination IP addresses  and source and destination  port before performing the calculation  but I still don’t get the correct queue.


In case you use RTE_ETH_HASH_SYMMETRIC_TOEPLITZ , the I40E key doesn’t change - Right ?
How do I find that the NIC does for symmetric hash so I can simulate it ?

(src="1.0.0.1", dst="2.0.0.2")/TCP(sport=8819, dport=80)

Actual queue - 7 (32 RX queues)



Result with XOR:

dpdk-rss-flows.py -s 8819 -d 80 -k i40e 32 1.0.0.1 2.0.0.2

SRC_IP     SPORT    DST_IP     DPORT    QUEUE

1.0.0.1    8819     2.0.0.2    80       19



Result without (original script):

dpdk-rss-flows.py -s 8819 -d 80 -k i40e 32 1.0.0.1 2.0.0.2

SRC_IP     SPORT    DST_IP     DPORT    QUEUE

1.0.0.1    8819     2.0.0.2    80       20





Thanks in advance,
Shaul.



From: "Lukáš Šišmiš" <sismis@cesnet.cz>

To: Balakrishnan K <Balakrishnan.K1@tatacommunications.com>,

        Stephen Hemminger <stephen@networkplumber.org>

Cc: "users@dpdk.org" <users@dpdk.org>

Subject: Re: Symmetric RSS Hashing support in DPDK<https://inbox.dpdk.org/users/90dc11cf-8c60-4b90-a3fc-43b2351b6c93@cesnet.cz/#r>

Date: Fri, 8 Mar 2024 08:29:32 +0100  [thread overview]<https://inbox.dpdk.org/users/90dc11cf-8c60-4b90-a3fc-43b2351b6c93@cesnet.cz/#r>

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Hi all,



I've made minimalist example app on how to set symmetric RSS support for

X710 that uses RTE_FLOW rules - check it out here:



https://github.com/lukashino/i40e-symmetric-rss-rte-flow



Lukas



On 08. 03. 24 6:53, Balakrishnan K wrote:

> 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@networkplumber.org>

> Sent: Wednesday, March 6, 2024 8:34 PM

> To: Balakrishnan K <Balakrishnan.K1@tatacommunications.com>

> Cc: users@dpdk.org

> Subject: Re: Symmetric RSS Hashing support in DPDK

>

> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.

>

> On Wed, 6 Mar 2024 07:28:40 +0000

> Balakrishnan K <Balakrishnan.K1@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



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