RISC-V Design · All levels

Register Conventions and Calling Discipline: Silicon PPA Impact

Silicon PPA Impact for Register Conventions and Calling Discipline.

Silicon PPA impact

Silicon PPA Impact for Register Conventions and Calling Discipline is anchored on Function-call overhead (instructions per call), spill/reload rate, and ABI conformance pass rate in integration tests.. Convert observations into mechanism-backed decisions with explicit ownership.

  • Frequency gains that increase bubbles may lose net throughput.

  • Area growth from extension logic must justify workload value.

  • Power and thermal stability are release gates, not secondary metrics.

PPA trend view

diagram
BEFORE / AFTER TREND - Register Conventions and Calling Discipline

Function-call overhead (instructions per call), spill/reload rate, and ABI conformance pass rate in integration tests.
  ^
  |                           o target band
  |                    o after fix + reruns
  |             o
  |      o baseline (failing)
  +--------------------------------------------------> iteration
       capture issue      isolate mechanism      close + monitor

Use this view to confirm the gain is causal and stable across seeds.