Topographical Synthesis: Reports & Metrics

Reports and metrics

Reports & Metrics for Topographical Synthesis focuses on topo-vs-logic WNS delta, estimated wirelength, congestion hotspots. The goal is to connect observed QoR movement to mechanism, ownership, and regression risk.

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

Metric movement

QOR TREND — Topographical Synthesis

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

Track: topo-vs-logic WNS delta, estimated wirelength, congestion hotspots

• Track topo-vs-logic WNS delta, estimated wirelength, congestion hotspots 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

Physical-aware synthesis reduces logic-to-route surprise when correlation is monitored.

Concept diagram

PHYSICAL-AWARE LOOP

topo compile -> congestion hints -> handoff -> PD correlation

Metric graph

CORRELATION DELTA

logic view WNS      ███████
topo view WNS       █████
route trial WNS     ████

Reports and artifacts

• topo QoR

• congestion heatmap

• handoff manifest

• delta compare vs PD

Mini case study

Topo compile looked clean, but hotspot congestion predicted route failure and prevented late ECO churn.

Debug branches

• Check hotspot ownership

• Bound correlation drift

• Escalate if handoff assumptions stale

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