We are encountering an issue with our ConnectX-6 Dx network card, where we have observed periodic increases in the ‘rx_prio0_buf_discard’ metric read from the “ethtool -S” and “mlnx_perf -i”.
rx.vport_unicast_packets: 2863 387.20
rx_vport_unicast.bytes: 824,148.379.49 Bps = 6,593.18 Mbps
tx_vport_unicast_bytes: 6,384,766,196.33 Bps = 5,1078.12 Mbps
rx_vport_multicast_bytes: 18.83 Bps
tx_vport_multicast_bytes: 4.13 Bps
rx_vport_rdma_unicast packets: 0.3
rx.vport_rdma_unicast bytes: 4.65 Bps
tx bytes_phy: 6,408,938,945.26 Bps = 51271.44 bps
rx bytes_phy: 824.243574.75 Bps = 6 593 94 Mbps
rx_oversize_pkts_phy: .24= 3.31 Mbps
rx_64 bytes_phy: 413,800.61 .Bps1.653.120.23
rx_prio0_bytes: 824,245,239.68 Bps
tx_prio0_bytes: 6408 913 331.13 Bps = 51,271.30 Mbps
Up 0: 51,271.36. Mbps= 100.00%
up0: 6,841,897.65 Tran/sec = 100.
We would appreciate your assistance in addressing the following concerns:
- Does the increase in this metric indicate packet loss?
- What could be the potential causes of this issue, and how can it be resolved? Would it require tunning or a firmware upgrade?
Here are the details of our environment for your reference:
- Network Card Model: ConnectX-6 Dx
- Firmware Version: 22.34.4000
- Operating System: Rocky Linux 8.8
- Application: Based on DPDK 21.11.4 with the mlx5 delay drop feature enabled. EAL Parameters: rxq_cqe_comp_en=4, allow_duplicate_pattern=0, delay_drop=0x1, rxq_pkt_pad_en=0x1, txq_inline_max=128, txq_inline_mpw=128
We have consulted the article “UNDERSTANDING MLX5 ETHTOOL COUNTERS” (https://community.mellanox.com/s/article/understanding-mlx5-ethtool-counters) to gain insights into the ‘rx_prio0_buf_discard’ metric. However, the explanations were unclear and lacked actionable guidance for resolving our issue.
Additionally, we attempted to address the problem by utilizing the tuning tool ‘mlxn_tune’ with the ‘HIGH_THROUGHPUT’ parameter. Unfortunately, this approach did not yield the desired results, as the issue with the rx_prio0_buf_discard metric persists.
We would greatly appreciate any further assistance or recommendations you could provide to help us resolve this matter effectively.