Warning logs from orchagent mcCounterCheck #4034
Description
We've observed excessive warning logs from orchagent’s mcCounterCheck() (branch 202405).
Oct 28 20:41:11.573963 sonic WARNING swss#orchagent: :- mcCounterCheck: Got Multicast 54 frame(s) on lossless queue 3 port Ethernet8
Oct 28 20:41:11.575612 sonic WARNING swss#orchagent: :- mcCounterCheck: Got Multicast 54 frame(s) on lossless queue 3 port Ethernet12
Oct 28 20:41:11.580911 sonic WARNING swss#orchagent: :- mcCounterCheck: Got Multicast 53 frame(s) on lossless queue 3 port Ethernet24
Oct 28 20:41:11.582824 sonic WARNING swss#orchagent: :- mcCounterCheck: Got Multicast 54 frame(s) on lossless queue 3 port Ethernet28
Oct 28 20:41:11.584527 sonic WARNING swss#orchagent: :- mcCounterCheck: Got Multicast 47 frame(s) on lossless queue 3 port Ethernet32
It seems mcCounterCheck() logic is trying to determine if a multicast queue is lossy or loss by using the PFC mask for unicast queues. In this case, there are 8 ucast queues and 4 mcast queues. We have PFC enabled for UC3 and UC4, but no settings for MC queues. However, both UC3 and MC11 have index 3, and the counter on MC11 triggers the warning from mcCounterCheck() as it considers MC11 also lossless.
$ queuestat -p Ethernet8
For namespace :
Port TxQ Counter/pkts Counter/bytes Drop/pkts Drop/bytes EcnWredMarked/pkts EcnWredMarked/bytes
--------- ----- -------------- --------------- ----------- ------------ -------------------- ---------------------
Ethernet8 UC0 1003283 321704286 0 0 0 0
Ethernet8 UC1 631310097 805931903719 0 0 0 0
Ethernet8 UC2 2611 704739 0 0 0 0
Ethernet8 UC3 0 0 0 0 0 0
Ethernet8 UC4 0 0 0 0 0 0
Ethernet8 UC5 0 0 0 0 0 0
Ethernet8 UC6 92 9752 0 0 0 0
Ethernet8 UC7 2324735 181997968 0 0 0 0
Ethernet8 MC8 166276 10730924 0 0 0 0
Ethernet8 MC9 0 0 0 0 0 0
Ethernet8 MC10 0 0 0 0 0 0
Ethernet8 MC11 874657 56188014 0 0 0 0
Has someone seen this issue as well?