RISC-V Design · All levels
Formal Pipeline Checks: Worked Example
Worked Example for Formal Pipeline Checks.
Worked example
Worked Example for Formal Pipeline Checks is anchored on Proof closure on pipeline safety/liveness properties with bounded-depth convergence and vacuity review.. Convert observations into mechanism-backed decisions with explicit ownership.
A regression flags Proof closure on pipeline safety/liveness properties with bounded-depth convergence and vacuity review.. Strong closure isolates first failing mechanism, proves causality, applies one bounded change, and validates blast radius.
System view
RISC-V PIPELINE DIAGRAM - Formal Pipeline Checks
PC -> IF -> ID -> EX -> MEM -> WB
| | | | |
i-cache decode ALU/BR LSU regfile write
\ |
+-> branch resolve + redirect
Hot paths:
- branch + load-use dependencies in ID/EX
- memory latency stretching MEM stage
- writeback arbitration for integer/vector units
Focus: keep control hazards predictableEvidence matrix
RISC-V EVIDENCE MATRIX - Formal Pipeline Checks
+--------------------------+--------------------------------+--------------------------------+---------------------------+
| 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 |
+--------------------------+--------------------------------+--------------------------------+---------------------------+Capture baseline and failing traces under fixed metadata tags.
Classify stage loss and dominant mechanism.
Collect Property dashboard including assumptions, proof status, vacuity outcomes, and counterexample triage log..
Apply one bounded fix with owner signoff.
Run validation matrix and decide ship/rollback.