Re: configuring RSS offloads with Netvsc PMD

[Nandini Rangaswamy <nandini.rangaswamy@broadcom.com>]

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Hi Stephen,
It does not work because the netvsc device is not initialized with
RTE_ETH_RSS_NONFRAG_IPV6_UDP
capability according to the below snippet.

static void hn_rss_hash_init(struct hn_data *hv,
const struct rte_eth_rss_conf *rss_conf)
{
/* Convert from DPDK RSS hash flags to NDIS hash flags */
hv->rss_hash = NDIS_HASH_FUNCTION_TOEPLITZ;

if (rss_conf->rss_hf & RTE_ETH_RSS_IPV4)
hv->rss_hash |= NDIS_HASH_IPV4;
if (rss_conf->rss_hf & RTE_ETH_RSS_NONFRAG_IPV4_TCP)
hv->rss_hash |= NDIS_HASH_TCP_IPV4;
if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6)
hv->rss_hash |= NDIS_HASH_IPV6;
if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6_EX)
hv->rss_hash |= NDIS_HASH_IPV6_EX;
if (rss_conf->rss_hf & RTE_ETH_RSS_NONFRAG_IPV6_TCP)
hv->rss_hash |= NDIS_HASH_TCP_IPV6;
if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6_TCP_EX)
hv->rss_hash |= NDIS_HASH_TCP_IPV6_EX;

memcpy(hv->rss_key, rss_conf->rss_key ? : rss_default_key,
NDIS_HASH_KEYSIZE_TOEPLITZ);
}

Since hn_dev_info_get merges the configuration of the netvsc device and VF
using AND operation(in hn_vf_info_merge), even though VF(MLX5)
supports RTE_ETH_RSS_NONFRAG_IPV6_UDP
, the netvsc driver does not return this capability support to the app.
Why is RTE_ETH_RSS_NONFRAG_IPV6_UDP capability not supported by the netvsc
driver?

Regards,
Nandini

On Thu, Aug 29, 2024 at 9:11 AM Nandini Rangaswamy <
nandini.rangaswamy@broadcom.com> wrote:

> Hi Stephen,
> It does not work because the netvsc device is not initialized with RTE_ETH_RSS_NONFRAG_IPV6_UDP
> capability according to the below snippet.
>
> static void hn_rss_hash_init(struct hn_data *hv,
> const struct rte_eth_rss_conf *rss_conf)
> {
> /* Convert from DPDK RSS hash flags to NDIS hash flags */
> hv->rss_hash = NDIS_HASH_FUNCTION_TOEPLITZ;
>
> if (rss_conf->rss_hf & RTE_ETH_RSS_IPV4)
> hv->rss_hash |= NDIS_HASH_IPV4;
> if (rss_conf->rss_hf & RTE_ETH_RSS_NONFRAG_IPV4_TCP)
> hv->rss_hash |= NDIS_HASH_TCP_IPV4;
> if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6)
> hv->rss_hash |= NDIS_HASH_IPV6;
> if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6_EX)
> hv->rss_hash |= NDIS_HASH_IPV6_EX;
> if (rss_conf->rss_hf & RTE_ETH_RSS_NONFRAG_IPV6_TCP)
> hv->rss_hash |= NDIS_HASH_TCP_IPV6;
> if (rss_conf->rss_hf & RTE_ETH_RSS_IPV6_TCP_EX)
> hv->rss_hash |= NDIS_HASH_TCP_IPV6_EX;
>
> memcpy(hv->rss_key, rss_conf->rss_key ? : rss_default_key,
> NDIS_HASH_KEYSIZE_TOEPLITZ);
> }
>
> Since hn_dev_info_get merges the configuration of the netvsc device and VF
> using AND operation(in hn_vf_info_merge), even though VF(MLX5) supports RTE_ETH_RSS_NONFRAG_IPV6_UDP
> , the netvsc driver does not return this capability support to the app.
> Why is RTE_ETH_RSS_NONFRAG_IPV6_UDP capability not supported by the
> netvsc driver?
>
> Regards,
> Nandini
>
>
>
> On Wed, Aug 28, 2024 at 12:05 PM Stephen Hemminger <
> stephen@networkplumber.org> wrote:
>
>> On Wed, 28 Aug 2024 10:32:17 -0700
>> Nandini Rangaswamy <nandini.rangaswamy@broadcom.com> wrote:
>>
>> > Hi Long and Stephen,
>> > I am trying to configure RSS offloads from my DPDK App with netvsc PMD.
>> > Netvsc seems to be supporting the following offloads:
>> > RTE_ETH_RSS_NONFRAG_IPV4_UDP RTE_ETH_RSS_NONFRAG_IPV4_TCP
>> > RTE_ETH_RSS_NONFRAG_IPV6_TCP RTE_ETH_RSS_IPV4
>> > RTE_ETH_RSS_IPV6
>> >
>> > However, the app is trying to configure the following offloads and
>> failing:
>> >
>> > RTE_ETH_RSS_NONFRAG_IPV4_UDP
>> > RTE_ETH_RSS_NONFRAG_IPV4_TCP
>> > RTE_ETH_RSS_NONFRAG_IPV6_TCP
>> > RTE_ETH_RSS_NONFRAG_IPV6_UDP
>>
>> Confusing, both of these overlap should work.
>> Please instrument the configure code in netvsc to see why it is
>> complaining.
>>
>> >
>> > Is it possible to bypass the netvsc PMD and configure these offloads on
>> VF
>> > ? I am aware that app should not directly program the VF interface
>> > but for performance sake, I want the above offloads to be supported on
>> VF.
>>
>> No can't bypass driver.
>>
>> You do need to configure multiqueue and enable RSS in configure
>> to get anything.
>>
>> If you look at hn_rss_hash_init, the driver needs to convert the
>> requested flags into NDIS flags to tell the host what to do.
>>
>

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