resq.stp prints the true SYN Queue length. This gives similar to
ss -n state syn-recv, but is more versatile. Example usage:
$ sudo stap -g resq.stp `pidof -s nginx` 5
PID=31905 FD=5
TASK=0xffff881f3a521d40
sk=0xffff882079b34380
reqsk_queue_len=6
reqsk_queue_len=9
...
acceptq.stp prints the size of both SYN as well as Accept queues
when the Listen Drop occurs. This is very useful for debugging spiky
applications that get stuck only for a short amount of time, but
enough to cause ListenDrop counters to raise. Example usage showing
struggling socket:
$ sudo stap -v acceptq.stp
time (us) acceptq qmax local addr remote_addr
1495634198449075 1025 1024 0.0.0.0:6443 10.0.1.92:28585
1495634198449253 1025 1024 0.0.0.0:6443 10.0.1.92:50500
1495634198450062 1025 1024 0.0.0.0:6443 10.0.1.92:65434