Synthesis & Logic Optimization · All levels

Timing-Driven Synthesis: Review Checklist

Review Checklist for Timing-Driven Synthesis.

Review checklist

Review Checklist for Timing-Driven Synthesis focuses on critical path WNS, violating endpoint count, compile effort distribution. The goal is to connect observed QoR movement to mechanism, ownership, and regression risk.

Run manifest is attached (RTL/SDC/libs/switches).
Primary metric and impacted lane are named.
Mechanism hypothesis is evidence-backed.
Fix is reversible and owner-assigned.
Regression matrix includes timing, area, power, and equivalence as needed.
Owners signed: synthesis lead, STA owner.

Sign-off ownership

diagram

OWNERSHIP MAP — Timing-Driven Synthesis

artifact              owner
----------------      -----------------
compile owner       synthesis lead
timing/power owner  STA owner

Every QoR movement needs a named owner before ECO.

Synthesis deep dive

Mapping converts logic intent into real PPA outcomes.

Concept diagram

diagram

MAPPING LOOP

boolean net -> library mapping -> optimization -> report and iterate

Metric graph

diagram

MAPPING IMPACT

depth reduction   ███████
fanout cleanup    █████
runtime overhead  ███

Reports and artifacts

mapping summary
critical path cell list
fanout/slew report
library coverage

Mini case study

Cell-heavy critical path improved after restructuring, while blanket buffering had worsened power.

Debug branches

Depth issue -> structure
Fanout issue -> buffers
Library mismatch -> view audit

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.

Principal synthesis review addendum

Timing-driven compile focuses optimization where slack is most constrained, balancing global QoR instead of over-optimizing non-critical logic.

Metric: critical path WNS, violating endpoint count, compile effort distribution

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