mlnx_qos configuration while dropping with DPDK 21.11

[Filip Janiszewski]

Hi,

I've an issue where my mellanox card can't get any faster than 75Mpps
(64 bytes frame) before starting to drop, and even that 75Mpps speed is
maintained just for a short time, then it gets even slower to round
55Mpps.. (Not having the same issue with an Intel E810 using the same
exact setup and DPDK version).

What would be the proper configuration for mlnx_qos so that I get the
best performance for 64bytes frame? (Or perhaps there's some other MLX
tool to use??) Please note I disable pause frame, and ethtools shows the
following counters increasing:

.
     rx_prio0_bytes: 1272663864199
     rx_prio0_packets: 3681438138
     rx_prio0_discards: 775995466
     tx_prio0_bytes: 72430
     tx_prio0_packets: 421
.

Only prio0 discards increase for some reason, not sure how to properly
configure the card to increase the performance.

There are some resources on the internet regarding mellanox
configuration, but are all a bit vague on what to do.

According to
https://fast.dpdk.org/doc/perf/DPDK_21_08_Mellanox_NIC_performance_report.pdf
The performance should be pretty much line rate for 64 bytes frame.

Thanks

-- 
BR, Filip
+48 666 369 823