RISC-V Design · All levels

Five-Stage Pipeline Partitioning and Timing Contracts: Expanded Case Study

Expanded Case Study for Five-Stage Pipeline Partitioning and Timing Contracts.

Expanded case study

Expanded Case Study for Five-Stage Pipeline Partitioning and Timing Contracts is anchored on Post-layout Fmax versus stage slack spread, plus bubble rate introduced by stage-boundary timing fixes.. Convert observations into mechanism-backed decisions with explicit ownership.

Use this page to rehearse complete review flow: symptom intake, mechanism split, evidence request, owner assignment, bounded fix, and closure decision.

Root-cause tree

diagram
ROOT CAUSE TREE - Five-Stage Pipeline Partitioning and Timing Contracts

Post-layout Fmax versus stage slack spread, plus bubble rate introduced by stage-boundary timing fixes. regressed
          |
   reproducible on fixed seed?
      /                 \
    no                   yes
    |                     |
env/tool drift       first failing domain?
                     /        |         \
                  decode    execute    memory/MMU
                    |         |            |
               control map  bypass/FU   TLB/walk/perm
                    |
         privilege/CSR side effects checked?

Stop at first confirmed mechanism, then assign explicit owner + fix proof.

Evidence matrix

diagram
RISC-V EVIDENCE MATRIX - Five-Stage Pipeline Partitioning and Timing Contracts

+--------------------------+--------------------------------+--------------------------------+---------------------------+
| Evidence                 | Tells you                      | Does not prove                 | Next action               |
+--------------------------+--------------------------------+--------------------------------+---------------------------+
| perf counter timeline    | where regression appears       | exact mechanism causality      | correlate with trace      |
| decode/control dump      | control intent per instruction | pipeline side-effect ordering  | inspect retire semantics  |
| trap + CSR logs          | privilege/fault behavior       | performance bottleneck alone   | pair with CPI buckets     |
| MMU/TLB walk trace       | translation behavior           | full system QoS impact         | test mixed workloads      |
| post-fix trend graph     | movement after fix             | long-term stability            | run stress matrix         |
+--------------------------+--------------------------------+--------------------------------+---------------------------+