Re: rss calculation as the nic

[Pavel Vazharov <freakpv@gmail.com>]

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On Wed, Feb 21, 2024 at 9:40 PM Yaron Illouz <yaroni@radcom.com> wrote:

> Hi Ori
>
> Thank you for your answer it helped me
>
> But I can see the load balancing is not done to the same instance for
> both directions
> I would like to have ip + port pairs arrive to same instance
>
> Now ip1+port1 -> ip2+port2 arrive to instance x and ip2+port2 -> ip1+port1
> arrive to another instance
>
> How can I solve this?
>
>
>
> *From:* Ori Kam <orika@nvidia.com>
> *Sent:* Wednesday, February 14, 2024 6:07 PM
> *To:* Yaron Illouz <yaroni@radcom.com>; dev@dpdk.org; 'users@dpdk.org' <
> users@dpdk.org>
> *Subject:* RE: rss calculation as the nic
>
>
>
> *EXTERNAL EMAIL:* Do not click links or attachments unless you recognize
> the sender and know the content is safe
>
>
>
> Hi Yaron,
>
>
>
> I can see some possible issues with your code, please see below.
>
If I understand your case correctly, you need to use a symmetric RSS key.
We use this one in production -
https://www.ndsl.kaist.edu/~kyoungsoo/papers/TR-symRSS.pdf
And you'll need to set it accordingly when configuring the device:
        port_conf.rx_adv_conf.rss_conf.rss_key     = rss_key;

        port_conf.rx_adv_conf.rss_conf.rss_key_len = rss_key_size;

HTH.


>
> *From:* Yaron Illouz <yaroni@radcom.com>
> *Sent:* Saturday, February 3, 2024 7:03 PM
> *To:* dev@dpdk.org; 'users@dpdk.org' <users@dpdk.org>
> *Subject:* rss calculation as the nic
>
>
>
> [Snip]
>
>
>
> static inline uint32_t
>
> do_softrss(struct rte_mbuf *m)
>
> {
>
>     uint32_t input_len;
>
>     struct rte_ipv4_tuple ipv4_tuple;
>
>
>
>     char * pRawPacket = static_cast<char*>(rte_pktmbuf_mtod(pi_mbuf, void*
> ));
>
>     IpHeader * pIpHeader = (IpHeader *)(pRawPacket + offsetOfIp);
>
>     if(pIpHeader->GetVersion()==4)
>
>     {
>
>         ipv4_tuple.src_addr =
> rte_be_to_cpu_32(pIpHeader->dwSrcAddressBigEndian);
>
>         ipv4_tuple.dst_addr =
> rte_be_to_cpu_32(pIpHeader->dwDstAddressBigEndian);
>
> [Ori] here you are converting BE to CPU
>
>         ipv4_tuple.sport = *(uint16_t*)(pRawPacket + transportLayerOffset);
>
>         ipv4_tuple.dport = *(uint16_t*)(pRawPacket +
> transportLayerOffset+2);
>
> [Ori] here you keep the values as BE
>
>         input_len = RTE_THASH_V4_L3_LEN;
>
>         return rte_softrss_be((uint32_t *)&ipv4_tuple, input_len,
> rss_key_be);
>
> [Ori] the above function expects to get everything in BE and  you should
> also call rte_convert_rss_key before the use of the above function.
>
>     }
>
>     return 0;
>
> }
>
> new_rss = do_softrss(mbuf_pointer);
>
> std::cout<< std::hex << mbuf_pointer->hash.rss << " -> " << new_rss <<
> std::dec << std::endl;
>
>
>
> And i get a different value than the mbuf_pointer->hash.rss
>
> 5ed28a5c -> 33eb33eb
>
> 974c1896 -> 24e224e2
>
> 1edf1638 -> 21752175
>
> 8a54c19 -> 80638063
>
> 459a6f76 -> 1b351b35
>
> 1cdf1d1c -> e53be53b
>
>
>
>
>
> ****  I understand it is possible to do it, but i don't get the same
> value  ***
>
> ethtool -i ens5f0
>
> driver: mlx5_core
>
> version: 5.8-3.0.7
>
> firmware-version: 22.32.2004 (MT_0000000437)
>
> expansion-rom-version:
>
> bus-info: 0000:83:00.0
>
> supports-statistics: yes
>
> supports-test: yes
>
> supports-eeprom-access: no
>
> supports-register-dump: no
>
> supports-priv-flags: yes
>
>
>

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