[dpdk-users] mlx5 VF packet lost between rx_port_unicast_packets and rx_good_packets

["Yan, Xiaoping (NSB - CN/Hangzhou)" <xiaoping.yan@nokia-sbell.com>]

Hi,

When doing traffic loopback test on a mlx5 VF, we found there are some packet loss (not all packet received back ).

From xstats counters, I found all packets have been received in rx_port_unicast_packets, but rx_good_packets has lower counter, and rx_port_unicast_packets - rx_good_packets = lost packets
i.e. packet lost between rx_port_unicast_packets and rx_good_packets.
But I can not find any other counter indicating where exactly those packets are lost.

Any idea?

Attached is the counter logs. (bf is before the test, af is after the test, fp-cli dpdk-port-stats is the command used to get xstats, and ethtool -S _f1 (the vf used) also printed)
Test equipment reports that it sends: 2911176 packets, receives:  2909474, dropped: 1702
And the xstats (after - before) shows rx_port_unicast_packets 2911177,  rx_good_packets 2909475, so drop (2911177 - rx_good_packets) is 1702

BTW, I also noticed this discussion "packet loss between phy and good counter"
http://mails.dpdk.org/archives/users/2018-July/003271.html
but my case seems to be different as packet also received in  rx_port_unicast_packets, and I checked counter from pf  (ethtool -S ens1f0 in attached log), rx_discards_phy is not increasing.

Thank you.

Best regards
Yan Xiaoping