Post-M10, user-requested final benchmark campaign: 6 realistic
workloads (16-256 independent neurons in a shared-input dense-layer
shape, a random-seeded 2-layer network with real cross-node PSRAM
forwarding, and a 6-node 2-hop dependency diamond) x 4 concurrency
levels (N_SLOTS=1/2/4/8) through the real, full neural_multiprocessor
system (real V1 PSRAM chain, real slot_mem_arbiter). 24/24 runs PASS
bit-exact against a software golden model (11,520 individual neuron/
node checks, zero mismatches).
Three real bugs found and fixed during the campaign itself (ERR-0009):
1. neural_director.v (M5) had a real RTL bug at N_SLOTS=1
($clog2(1)=0 makes a replication expression illegal) - never
caught because M5-M10 only ever tested N_SLOTS=2/4/8. Fixed with
a width-agnostic '0 literal; M5's own testbench re-verified
unaffected.
2/3. Two testbench sizing bugs in tb_benchmark_suite.v itself
(psram_model DEPTH too small for the Large workload's address
range; N_NODES too small for the Stress workload's node-id range,
causing a real deadlock via node-id wraparound colliding with an
already-DISPATCHED node - a real, honest consequence of DEC-0008's
own "no node-slot reclamation" design choice).
Headline finding: real parallel scaling is essentially flat beyond
N_SLOTS=2 - the single shared PSRAM port saturates at ~91%
utilization regardless of slot count, so memory-bound workloads gain
only 1.05-1.06x real speedup from N=1 to N=8. Once real POST-P&R Fmax
degradation is also factored in, N_SLOTS=4 is measurably 21% SLOWER
in real wall-clock time than N_SLOTS=1 for the largest workload
tested. N_SLOTS=2 is recommended as the default (DEC-0014,
superseding DEC-0012's resource-only "N_SLOTS=8 ceiling" framing for
general use).
Full 21-section report (every number classified THEORETICAL/
SIMULATED/POST-P&R MEASURED/DERIVED, per the user's own
methodology requirements): hardware/v2/docs/benchmarks/
final-benchmark.md
Logged: simulation/synthesis/timing/benchmark/decisions (DEC-0014)/
experiments (EXP-0014)/errors (ERR-0009)/development.log,
ROADMAP.md updated.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
micheleandClaude Sonnet 5
3cdaeaee35