Inflight value shown invalid in Event Dev Queue

[Van Haaren, Harry]

> From: Hari Haran <info2hariharan at gmail.com> 
> Sent: Wednesday, July 19, 2023 1:39 PM
> To: users at dpdk.org
> Subject: Inflight value shown invalid in Event Dev Queue
>
> Hi All,

Hi Hari Haran,

> Once packets dequeued from port 0, still inflight stats shown same as dequeued count. 
> After that, enqueue failure happens for port 2 from another core due to it reaches Max Enqueue depth .

This describes what happens -> it would be helpful to know what you are expecting to happen.
Would you describe what each of port 0,1,2 are actually used for, and how events are expected
to flow from RX to a Port through a Queue, to another Port, until TX?

Describing the expectation and then comparing that to your "problem description" in this email often
leads to the root cause & solution.

Keep in mind that the event/sw implementation has capacity limitations. It seems to be too  high in your configuration
(inflight = 32768 is a indicator of an issue, as SW_INFLIGHT_EVENTS_TOTAL is 4096 in sw_evdev.h).

> Port 0 Stats:
> 
> Below case, port 0 dequeued 4096 packets and still inflight showed the same value.

How are the events being re-enqueued? 

> Port 0
>   rx   0  drop 0  tx   4096   inflight 4096  
> 
> Full Stats:
> 
> Dev=0 Port=1EventDev todo-fix-name: ports 3, qids 1
> rx   32768
> drop 0
> tx   4096
> sched calls: 628945658
> sched cq/qid call: 628964843
> sched no IQ enq: 628926401
> sched no CQ enq: 628942982
> inflight 32768, credits: 0
> 
> Port 0
>   rx   0  drop 0  tx   4096   inflight 4096
>   Max New: 32768  Avg cycles PP: 0    Credits: 0
>   Receive burst distribution:
>       0:100% 1-4:0.00% 5-8:0.00% 9-12:0.00%
>   rx ring used:    0 free: 4096
>   cq ring used:    0 free:  128
> Port 1
>   rx   0  drop 0  tx   0  inflight 0
>   Max New: 32768  Avg cycles PP: 0    Credits: 0
>   Receive burst distribution:
>       0:100%
>   rx ring used:    0 free: 4096
>   cq ring used:    0 free:  128
> Port 2
>   rx   32768  drop 0  tx   0  inflight 0
>   Max New: 32768  Avg cycles PP: 0    Credits: 0
>   Receive burst distribution:
>       0:-nan%
>   rx ring used:    0 free: 4096
>   cq ring used:    0 free:  128
> 
> Queue 0 (Atomic)
>   rx   32768  drop 0  tx   4096
>   Per Port Stats:
>     Port 0: Pkts: 4096    Flows: 1
>     Port 1: Pkts: 0   Flows: 0
>     Port 2: Pkts: 0   Flows: 0
>     Port 3: Pkts: 0   Flows: 0
>   iq 0: Used 28672
> This issue will be resolved once system level restart is done.
> Kindly give insight on this issue, if you found any clues. 
> TIA.
> 
> Regards
> Hariharan

Regards, -Harry van Haaren (PS: our names are surprisingly similar! : )