Datapath Debug: Reports & Metrics

Reports and metrics

Reports & Metrics for Datapath Debug focuses on datapath QoR regression rate, functional mismatch escapes, root-cause latency. The goal is to connect observed QoR movement to mechanism, ownership, and regression risk.

A report is useful only when it supports decisions. For Datapath Debug, read metric movement with baseline context and expected budget.

Metric movement

QOR TREND — Datapath Debug

metric quality
  ^
  |                      target band
  |                o  o  o
  |            o
  |      o  regression
  +----------------------------------> synthesis iteration
   baseline    tuning     signoff-ready

Track: datapath QoR regression rate, functional mismatch escapes, root-cause latency

• Track datapath QoR regression rate, functional mismatch escapes, root-cause latency with exact run manifests.

• Keep timing/area/power side-by-side in review dashboards.

• Require one-sentence mechanism hypothesis for every major delta.

• Store before/after artifacts with owner signoff.

Synthesis deep dive

Datapath and retiming gains are only real if formal and timing remain clean.

Concept diagram

DATAPATH + RETIME

operator inference -> stage balancing -> formal proof -> QoR validation

Metric graph

FREQUENCY VS LATENCY

Fmax gain   ████████
latency cost ████

Reports and artifacts

• retiming report

• datapath inference log

• equivalence status

• latency impact sheet

Mini case study

Retiming met frequency target, but missing formal hooks delayed closure by two days.

Debug branches

• Check retime blockers

• Formal first for aggressive moves

• Compare with pipeline option

Senior review question

Ask: what evidence proves this QoR move is real and stable?

Key takeaways

• State exact run context (RTL, SDC, libs, switches) with every QoR claim.

• Re-run timing, area, and power regressions after each synthesis ECO.

Common pitfalls

• Comparing runs with mismatched constraints or library views.

• Timing-only fixes that violate power or area budgets.

• Skipping equivalence checks after structural changes.

Report reading lens