Synthesis & Logic Optimization · All levels
QoR Dashboard & Trend Triage: Comparison Matrix
Comparison Matrix for QoR Dashboard & Trend Triage.
Comparison matrix
Constraint and policy choices trade closure speed against regression risk.
+------------------+----------------+----------------+----------------+
| Approach | Strength | Weakness | Best when |
+------------------+----------------+----------------+----------------+
| Conservative | stable | slower | new design spin |
| Balanced | practical | needs monitoring | normal closure |
| Aggressive | fast | higher risk | schedule crunch |
| Structural | durable | long loop | repeat offender |
+------------------+----------------+----------------+----------------+When to choose each approach
Select strategy by risk budget, not convenience.
Interview traps
Skipping manifest diff
No side-effect regression
Evidence comparison
SYNTHESIS EVIDENCE MATRIX — QoR Dashboard & Trend Triage
+--------------------+------------------------+--------------------------+-------------------------+
| Evidence | Tells you | Does not prove | Next action |
+--------------------+------------------------+--------------------------+-------------------------+
| compile QoR report | metric movement | root-cause class | inspect transform logs |
| SDC diff | constraint drift | library quality | rerun with baseline SDC |
| library map diff | cell view changes | RTL intent quality | lock/validate lib set |
| topo vs logical QoR | physical correlation | final route signoff | PD trial correlation |
| regression matrix | closure stability | architecture optimality | decide merge/rollback |
+--------------------+------------------------+--------------------------+-------------------------+Synthesis deep dive
Constraint hygiene determines whether synthesis QoR is trustworthy.
Concept diagram
CONSTRAINT FLOW
RTL intent -> synthesis SDC -> compile checks -> QoR dashboard -> review gateMetric graph
QOR HEALTH
constraint lint pass ███████████████
unconstrained count ███
policy violations ██Reports and artifacts
compile QoR
unconstrained endpoints
constraint lint
policy audit log
Mini case study
Nightly WNS improved but unconstrained paths jumped; strict SDC lint restored true QoR picture.
Debug branches
Diff SDC first
Audit dont_touch scope
Track unconstrained trend weekly
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
QoR closure is a trend-management problem: dashboard baselines catch regressions early and keep optimization decisions tied to measurable outcomes.
Metric: WNS/TNS trend, area delta, dynamic/leakage trend, compile runtime