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Hazard Detection Basics in Decode: Expanded Case Study

Expanded Case Study for Hazard Detection Basics in Decode.

Expanded case study

Expanded Case Study for Hazard Detection Basics in Decode is anchored on RAW stall cycles per kilo-instruction and percentage of avoidable stalls removed by forwarding.. 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 - Hazard Detection Basics in Decode

RAW stall cycles per kilo-instruction and percentage of avoidable stalls removed by forwarding. 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 - Hazard Detection Basics in Decode

+--------------------------+--------------------------------+--------------------------------+---------------------------+
| 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         |
+--------------------------+--------------------------------+--------------------------------+---------------------------+