DOCA PCC Counters (pcc_counters.sh)

Where to start: This is a tool skill for invoking pcc_counters.sh — a small bash script that arms and reads the device's fixed set of firmware / hardware PCC diagnostic counters (CNP count, RTT-perf, WRED-drop, RTT-gen, handled events) through the mlx5 debugfs diag_cnt interface. Open TASKS.md and start at ## run for the canonical set-then-query sequence, or ## debug when the user reports "ERROR: Bad Device", "counter stuck at zero", or "the dump is empty". Open CAPABILITIES.md when the question is which counters the script reports and how it reaches them. If the user has not installed DOCA / MFT yet, route to doca-setup first.