micheleandClaude Sonnet 5
1ce78dff6e
EXP-0056: N_SLOTS=16 failed timing on LFE5U-85F (23-24MHz vs 64MHz
target). First hypothesis (dependency_manager.v's serial ready-scan)
was wrong but real -- built and verified priority_encoder_lsb.v (a
generic recursive tree encoder) and dependency_manager_fast.v, bit-
exact equivalent to the original, but integrated it made no real
difference (24.26MHz). The real cause, found from nextpnr's own
critical-path report: nms_activation_fill_ctrl_v3.v's balanced max-
tree was only ever extended to N_SLOTS in {1,2,4,8}, silently falling
back to the original slow scan for 16. Added the missing case
(nms_activation_fill_ctrl_v3_n16.v), verified isolated (10017/10017)
and functionally (D-Stress N=16 still 256/256 bit-exact). Real result:
71.01MHz, PASS at 64MHz (single seed so far).
EXP-0057: built layer_weight_buffer.v, a double-buffered per-layer
weight scratchpad (fill one buffer in the background from SDRAM while
compute reads many times from the other -- weight-stationary reuse,
as opposed to D-Stress's own deliberately zero-reuse pattern). Wired
to the real sdram_controller_openrow.v + sdram_model.v, no new
hardware. For the same 32768 bytes of useful data: zero-reuse costs
27048 real cycles, reuse costs 3777 -- 7.16x real measured speedup on
the SAME SDR SDRAM, no DDR3, no clock change. This is the answer to
whether DDR3 is necessary for a workload class that actually has
reuse (e.g. conv-style face recognition, unlike D-Stress) -- it isn't,
at least not for this reason.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
Formato dei log V2
Regola non negoziabile (docs/v2-description.md §25-29): ogni attività
significativa (modifica, simulazione, sintesi, benchmark, decisione, errore)
deve essere registrata. Nessun log viene mai sovrascritto o troncato — solo
append. Nessun ID esperimento (EXP-XXXX) o decisione (DEC-XXXX) viene mai
riutilizzato, anche se il risultato è un FAIL.
File
development.log— log principale di sviluppo, un'entry per ogni sessione di lavoro/milestone (creazione file, refactor, avanzamento roadmap).architecture.log— decisioni e note di architettura a grana fine (non scelte finali — quelle vanno indecisions.log— ma esplorazioni, alternative considerate, vincoli scoperti).simulation.log— ogni run di simulazione (Icarus/Verilator): test, vettori, cicli, PASS/FAIL, confronto bit-exact con V1, stall/memory-wait.synthesis.log— ogni run Yosys: LUT/FF/DSP/BRAM, warning, problemi CHECK.timing.log— ogni run nextpnr-ecp5: Fmax, percorso critico, WNS/TNS se disponibili. Fmax "ufficiale" di una configurazione = solo da qui, mai da simulazione o stima.benchmark.log— tabelle di confronto per configurazione (Fmax, MAC/cycle, cycles/neuron, utilization, ecc.), sempre con etichetta THEORETICAL/SIMULATED/SYNTHESIZED/POST-P&R.decisions.log— decisioni architetturali importanti, formatoDEC-XXXX(vedidocs/v2-description.md§27).experiments.log— registro principale, unEXP-XXXXper ogni esperimento end-to-end (config → sim/synth/timing → risultato), rimanda areports/experiments/EXP-XXXX/.errors.log— errori/bug/regressioni incontrati durante lo sviluppo V2 stesso (non i bug V1, già chiusi inhardware/v1/docs/validation/bugs.md).
Campi minimi per entry (§26)
timestamp, experiment_id (se applicabile), git_commit, session/agent,
module, configuration, action, reason, command, result, errors, decision,
next_action
Per synthesis/timing aggiungere: LUT, FF, DSP, BRAM, Fmax, critical path, WNS/TNS. Per simulazione: test, vectors, cycles, PASS/FAIL, bit-exact result, stall cycles, memory wait, utilization.