If you look in the klippy.log file you’ll see “Stats” lines once a second during a print. Part of the line will look like: mcu: mcu_awake=0.034 mcu_task_avg=0.000028 mcu_task_stddev=0.000035 bytes_write=94552431 bytes_read=16958126 bytes_retransmit=604 bytes_invalid=0 send_seq=1707525 receive_seq=1707525 retransmit_seq=484586 srtt=0.001 rttvar=0.000 rto=0.025 ready_bytes=42 stalled_bytes=0 freq=71997236. This is information on the mcu status. The srtt report is the smooth-round-trip-time, the rttvar is the round-trip-time-variance, and rto is the retransmit-timeout. Other stats there may also be of interest in quantifying the health of the connection.
-Kevin
EDIT: This info is also available internally in Klipper - see the last_stats variable in the “mcu” status reference: Status reference - Klipper documentation