Thanks Stephen.

We reconfigure the RSS key via rte_eth_dev_rss_hash_update(). We just set it to the same default key value which is below just in case it changes in the future.

0x2c, 0xc6, 0x81, 0xd1, 0x5b, 0xdb, 0xf4, 0xf7,
0xfc, 0xa2, 0x83, 0x19, 0xdb, 0x1a, 0x3e, 0x94,
0x6b, 0x9e, 0x38, 0xd9, 0x2c, 0x9c, 0x03, 0xd1,
0xad, 0x99, 0x44, 0xa7, 0xd9, 0x56, 0x3d, 0x59,
0x06, 0x3c, 0x25, 0xf3, 0xfc, 0x1f, 0xdc, 0x2a,

Yes, we use accelerated network and our DPDK build includes mlx.

It happens on the first packet. However we don't know if subsequent packets will work as our application stops if the first is delivered incorrectly.

We don't use layered encapsulation. Our packets are standard UDP packets.

No, we use the standard ETH_RSS_NONFRAG_IPV4_UDP.

Yes, we print the rss field in rte_mbuf. It's not byte swapped from what I can tell.

21.08 has a feature we wanted at the time. We haven't had time to switch to a LTS version.

On Fri, Nov 4, 2022 at 3:18 PM Stephen Hemminger <stephen@networkplumber.org> wrote:

On Fri, 4 Nov 2022 10:15:36 -0700
Yang Luan <luan.penny@gmail.com> wrote:

> We use netvsc PMD (drivers/net/netvsc/).
> We don't explicitly configure the RETA table. We configure the device with
> 40 rx queues (rte_eth_dev_configure) and use rte_eth_dev_rss_reta_query()
> to query the RETA table (result posted earlier).

More questions to help someone (not me I don't have free Azure access now);
get a reproduction.

Did you reconfigure the RSS key?
The default for the netvsc PMD should be the same default as Mellanox.

Have you enabled accelerated networking (ie VF). If so then does your DPDK
build support Mellanox. Probably yes to both.

Is this the first packet, or later packets in the flow?
Are you using any layered encapsulation (like GRE or VXLAN), and/or IP options.

Are you changing RSS options so that is different than default L3/L4?

Are you printing the RSS key in the mbuf? It might be byte swapped.

Why 21.08? it is not a long term supported version, and therefore does not
receive bugfixes like:

$ git log --oneline v21.08..v20.11.6 -- drivers/net/netvsc/
9d474a9565a5 net/netvsc: fix vmbus device reference in multi-process
a61bd9df25dc net/netvsc: fix calculation of checksums based on mbuf flag
0b5a6c7b32c8 fix spelling in comments and strings
e97bb2a91151 net/netvsc: ignore unsupported packet on sync command