RISC-V Design · All levels

Privilege Levels, Execution Modes, and Delegation Boundaries: Silicon PPA Impact

Silicon PPA Impact for Privilege Levels, Execution Modes, and Delegation Boundaries.

Silicon PPA impact

Silicon PPA Impact for Privilege Levels, Execution Modes, and Delegation Boundaries is anchored on Privilege-transition latency and number of unauthorized accesses blocked by PMP/page-permission checks per billion instructions.. 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 - Privilege Levels, Execution Modes, and Delegation Boundaries

Privilege-transition latency and number of unauthorized accesses blocked by PMP/page-permission checks per billion instructions.
  ^
  |                           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.