Protocol Metrics Reference · protocols

Interface ProtocolsAll levels

Core metric families

Correctness: protocol violations, ordering escapes, stale data, ECC/CRC errors.
Performance: throughput, p99 latency, payload efficiency, retry rate, credit stalls.
Bring-up: enumeration success, link width/speed, training margin, boot failure rate.
Verification: compliance pass rate, coverage closure, waiver count, false fail rate.

Metric	Boundary and denominator to retain
Useful throughput	Enabled useful bytes on accepted transfers / elapsed seconds; name the interface, traffic and observation interval.
Conditional stall fraction	Samples with VALID && !READY / samples with VALID. With zero offers, report no offers rather than a misleading zero stall rate.
Payload efficiency	Useful payload bytes / transmitted bytes at the specified layer; idle time and retries need clearly separated accounting.
Latency percentile	Name admission and completion events, clock/time conversion, sample population and warm-up/cancellation handling.
Retry or error rate	Name the counter, direction, traffic class, interval and attempted/completed-work denominator; a counter alone does not identify a cause.
Verification result	Requirement, enabled checker, actual observed work, configuration/source revision and verdict; distinguish expected fault detection from compliance.