Re: [PATCH] net/vmxnet3: added checks for TCP for RSS Configuration

[Jochen Behrens <jbehrens@vmware.com>]

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The check is at an additional location. I agree, and pointed out to him offline earlier, that a check for the h/w version should be used with the additional code, too.

                Jochen



From: Ferruh Yigit <ferruh.yigit@amd.com>
Date: Friday, January 13, 2023 at 8:24 AM
To: Raghav Roy <royra@vmware.com>, dev@dpdk.org <dev@dpdk.org>
Cc: Jochen Behrens <jbehrens@vmware.com>
Subject: Re: [PATCH] net/vmxnet3: added checks for TCP for RSS Configuration
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On 12/22/2022 8:24 AM, Raghav Roy wrote:
> Added checks for TCP in vmxnet3_rss_configure()
> This check ensures the hashType for RSS, when enabled
> just for UDP, is not NONE.
>

Mandatory hash functions for v4 already added in the past:
Commit 52ec00fd1474 ("net/vmxnet3: fix RSS setting on v4")

Now this commit adds it for all versions, why it was fine in the past
but it is needed now?

@Jochen, can you please help reviewing this patch?


> Signed-off-by: Raghav Roy <royra@vmware.com>
> ---
>  drivers/net/vmxnet3/vmxnet3_rxtx.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c b/drivers/net/vmxnet3/vmxnet3_rxtx.c
> index a875ffec07..e8407c9b2e 100644
> --- a/drivers/net/vmxnet3/vmxnet3_rxtx.c
> +++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c
> @@ -1412,6 +1412,13 @@ vmxnet3_rss_configure(struct rte_eth_dev *dev)
>       dev_rss_conf = hw->rss_conf;
>       port_rss_conf = &dev->data->dev_conf.rx_adv_conf.rss_conf;
>
> +     if ((port_rss_conf->rss_hf & VMXNET3_MANDATORY_V4_RSS) !=
> +        VMXNET3_MANDATORY_V4_RSS) {
> +             PMD_INIT_LOG(WARNING, "RSS: IPv4/6 TCP is required for vmxnet3 RSS, "
> +                          "automatically setting it");
> +             port_rss_conf->rss_hf |= VMXNET3_MANDATORY_V4_RSS;
> +     }
> +

`
#define VMXNET3_MANDATORY_V4_RSS ( \
        RTE_ETH_RSS_NONFRAG_IPV4_TCP | \
        RTE_ETH_RSS_NONFRAG_IPV6_TCP)
`

Can you please describe why IPv4/6 TCP hash function is required for driver?
And what is the impact, I mean what is the observed behavior without
this patch, if RSS is failing without this change patch needs to be fix
patch and please describe since when RSS is failing.

>       /* loading hashFunc */
>       dev_rss_conf->hashFunc = VMXNET3_RSS_HASH_FUNC_TOEPLITZ;
>       /* loading hashKeySize */
> @@ -1419,6 +1426,7 @@ vmxnet3_rss_configure(struct rte_eth_dev *dev)
>       /* loading indTableSize: Must not exceed VMXNET3_RSS_MAX_IND_TABLE_SIZE (128)*/
>       dev_rss_conf->indTableSize = (uint16_t)((MAX_RX_QUEUES(hw)) * 4);
>
> +
>       if (port_rss_conf->rss_key == NULL) {
>               /* Default hash key */
>               port_rss_conf->rss_key = rss_intel_key;
> @@ -1446,6 +1454,5 @@ vmxnet3_rss_configure(struct rte_eth_dev *dev)
>               dev_rss_conf->hashType |= VMXNET3_RSS_HASH_TYPE_IPV6;
>       if (rss_hf & RTE_ETH_RSS_NONFRAG_IPV6_TCP)
>               dev_rss_conf->hashType |= VMXNET3_RSS_HASH_TYPE_TCP_IPV6;
> -

Please drop unrelated/unimportant syntax changes.

>       return VMXNET3_SUCCESS;
>  }


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