PD Handoff Reports

What this topic teaches

PD Handoff Reports teaches how to turn synthesis intent into stable QoR outcomes. Strong handoff packages constraints, scenario assumptions, and QoR baselines so PD can preserve intent and diagnose deltas quickly. Senior practice is proving whether metric movement is real, reproducible, and owned.

The senior-engineer question

When handoff completeness, view consistency, first-route QoR deviation moves, can you name the run context, mechanism, owner, and minimal fix that holds under regression?

SYNTHESIS FLOW — PD Handoff Reports

RTL + constraints
      |
      v
elaboration + checks
      |
      v
mapping + optimization
      |
      v
QoR reports (timing/area/power)
      |
      v
incremental ECO + regression

Primary metric: handoff completeness, view consistency, first-route QoR deviation

Picture the synthesis flow

Draw the behavior before diving into tool commands. These diagrams are the whiteboard models to memorize for reviews and interviews.

PD handoff package

netlist + SDC + scenario map
QoR baseline + assumptions
owner matrix + known risks

QoR trend shape

QOR TREND — PD Handoff Reports

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

Track: handoff completeness, view consistency, first-route QoR deviation

Who owns which layer

SYNTHESIS OWNERSHIP LAYERS — PD Handoff Reports

layer               owns                          failure mode
----------------    ---------------------------   -------------------------
constraints         clocks/exceptions/policy      fake QoR optimism
mapping             cell choices/structure        depth/fanout regressions
optimization        timing/power tradeoffs        one-metric overfitting
physical-aware      topo/congestion estimates     handoff delta surprises
closure             ECO order/regression          fixes break other corners

Evidence to collect

• Primary metric: handoff completeness, view consistency, first-route QoR deviation.

• Primary artifact: handoff manifest, baseline QoR snapshot, assumption checklist.

• Owners to involve: synthesis lead, PD lead, CAD owner.

• One baseline run and one regressed run with matching manifests.

• A rollback-safe change proposal with full regression scope.

Ownership map

OWNERSHIP MAP — PD Handoff Reports

artifact              owner
----------------      -----------------
compile owner       synthesis lead
timing/power owner  PD lead
cross-team review   CAD owner

Every QoR movement needs a named owner before ECO.

Subpages in this topic

Each topic is taught through mechanism, interfaces, reports, debug, worked example, pitfalls, interview, checklist, theory, design space, expanded case study, walkthrough, comparison matrix, software view, and silicon PPA impact.

Key takeaways

• Always present QoR with run context and artifact.

• Prefer reversible fixes with explicit rollback criteria.

• Re-run timing, area, and power checks before closing.

Common pitfalls

• Comparing unlike compile contexts.

• Timing-only wins that worsen power or area.

• Skipping equivalence checks after structural changes.

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.