Mellanox ConnectX-5 Tx performance issue

NIC: MCX516A-CCAT
DPDK 19.11, not configure any devargs
Enable 16 RxQ and 48 TxQ per port, both RxQ and TxQ size are 16384.

When we try to forward 100G 1500 byte size packets, about 12% packets cannot send out.
However, it can reach higher tx packet rate if forward 512 byte size packets.

hi jiantao,

How much pps when using 1500 frame size?
As you know, when using a smaller 512 frame size, the pps should get much higher compared to 1500.
The specific data can be found here:
https://fast.dpdk.org/doc/perf/DPDK_19_11_Mellanox_NIC_performance_report.pdf

Also, the above performance report lists test settings. It’s a good start to tune performance according to the suggestion.
Make sure all optimizations have been done before to performance test.

Regards,
Levei