e809b718064bff5aa0a38ea7a28ee8c2ad15277d
13
Commits
| Author | SHA1 | Message | Date | |
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  micheleandClaude Sonnet 5
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6a46dc857f |
fix: propagate runtime-indexed-crossbar fix to slot_mem_arbiter(_wide) + dataflow_core mux
DEC-0043: slot_mem_arbiter.v/slot_mem_arbiter_wide.v both still had the exact runtime-variable-indexed part-select anti-pattern (pending_addr[grant_idx*ADDR_WIDTH +: ADDR_WIDTH], grant_idx a runtime register) that neural_director.v had already found and fixed once before -- ADDR_WIDTH=26 not being a power of 2 means this synthesizes as a real multiplier + wide crossbar, sitting right on the arbiter<->backend boundary this project's own N=8 congestion diagnosis names, growing with N_PORTS=N_SLOTS(+1). Also fixed the cheaper but same-class dir_job_out_slot*16 mux in nms_dataflow_core_sdram.v, feeding directly into dependency_manager -- this exact signal was DEC-0042's own diagnosed N=4 critical path. Fix: N_PORTS/N_SLOTS parallel constant-indexed comparisons (unrolled for-loop) instead of a runtime-indexed read -- same technique already proven in neural_director.v. Purely an internal-implementation change. Verified bit-exact via Verilator: tb_fpga_neural_v2_top_smoke.v 11/11 PASS; tb_nms_dstress_sdram_unified.v (256-neuron stress) at both N_SLOTS_CFG=4 and =8, 256/256 bit-exact vs golden, total_cycles IDENTICAL to pre-fix historical values (49927/49909, exact match to DEC-0042's own recorded numbers). Bonus finding from the same D-Stress run (not this commit's main point, logged for Phase 3/4): sdram_busy_cycles ~81.6% and useful-MAC-cycle fraction HALVING from N=4 to N=8 (2.04%->1.02%) -- real existing evidence the system is memory-bound on a single SDRAM bank well before N=8, independent of Fmax. Re-synthesis (8-seed sweep, N=4/N=8) in progress to measure the actual Fmax delta from this fix -- committed separately once complete. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> |
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micheleandClaude Sonnet 5
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63cac6a7e5 |
perf(v2): shared activation cache - further 1.66-2.00x real speedup (DEC-0016)
Implements optimization #2 from the final benchmark campaign's own recommendation, on top of DEC-0015's word-level burst rewrite: a new shared activation_cache.v module fetches a given activation (X) vector from PSRAM once instead of once per neuron sharing it - the exact redundant traffic pattern the dense-layer workloads in this project's benchmark suite exhibit. Each memory_manager's own prefetch_engine now fetches WEIGHTS only; the activation half is requested from the shared cache instead (single-tag, tile-granular, N_SLOTS request ports, its own real word-level PSRAM backend via a new dedicated arbiter port). dataflow_core.v/slot_mem_arbiter.v/neural_multiprocessor.v widened to N_SLOTS+1 ports to arbitrate the cache's traffic alongside each slot's weight traffic. Two real bugs found and fixed during implementation (ERR-0010): a target-bank/pending-bank race in memory_manager.v's activation-cache wiring (the same bug class ERR-0006 already fixed once for pf_target_bank - a later handoff's queued request can overwrite which bank an earlier, still-in-flight request's ack applies to), and a repeat of ERR-0009's N_SLOTS=1 zero-width replication bug in activation_cache.v itself. Real, measured results: the full final-benchmark campaign (24/24 workload/config combinations) re-verified bit-exact. D-Stress cycles fall a further 1.66-2.00x on top of DEC-0015 (~4x combined vs the original byte-level baseline). But the cache's real Fmax cost is much steeper than DEC-0015's own: N_SLOTS=2 (the recommended default, DEC-0014) drops from 133.58 to 87.72 MHz (-34%, margin over 80MHz shrinks from +67% to +9.7%), and N_SLOTS=4 drops to 65.01 MHz - now FAILING the 80MHz target it previously passed. Combined real wall-clock speedup vs the original baseline: N=1 3.86x, N=2 2.45x (both real net wins); N=4 is a real regression once its own now-failing Fmax is honestly used, though N=4 was never the recommended configuration. N_SLOTS=2 remains the recommended default (DEC-0014 unaffected) with a thinner but still real Fmax margin. Cache hit-detection pipelining is flagged as concrete follow-up work if N_SLOTS>2 is ever needed with the cache active - not attempted this round. Logged: simulation/synthesis/timing/benchmark/decisions (DEC-0016)/ experiments (EXP-0016)/errors (ERR-0010)/development.log, ROADMAP.md updated. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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e4a5540b6e |
perf(v2): word-level burst reads - 2.24-2.37x real wall-clock speedup (DEC-0015)
Implements optimization #1 from the final benchmark campaign's own recommendation: exploit psram_controller.v's already-implemented page-mode support (confirmed present by direct inspection) by fetching multiple bytes per real backend transaction instead of one at a time. Root cause addressed: int8_memory_access.v (the byte-level backend prefetch_engine.v originally sat on) already converts every 8-bit logical request into a full 16-bit PSRAM word access internally (mem_addr <= addr >> 1), discarding half of every word it already paid for. prefetch_engine.v/memory_manager.v now speak memory_interface.v's own 16-bit word protocol directly, bypassing int8_memory_access.v entirely - which remains untouched, still frozen V1 (§1/§34); V2 simply reuses the lower layer of the same frozen chain instead of the byte-splitting layer on top of it, the same "reuse what fits" precedent slot_mem_arbiter.v already set. slot_mem_arbiter.v and neural_multiprocessor.v widened to match (lb_n/ub_n added, master port wired directly to memory_interface.v). Real, measured results: M4's own single-job testbench shows 49-56% fewer cycles (166->84, 446->204, 728->322, all still bit-exact). The full final-benchmark campaign (24/24 workload/config combinations) re-verified bit-exact with D-Stress's real wall-clock time (cycles / real POST-P&R Fmax) improving 2.24-2.37x across every N_SLOTS tested, against a small real Fmax cost (unchanged at N=1, -6.2% at N=2, -1.2% at N=4). tb_neural_multiprocessor.v (M8) and tb_benchmark_suite.v (final campaign) needed zero changes - both treat neural_multiprocessor.v as a black box. Only tb_memory_manager.v (M4, rewired to skip int8_memory_access.v) and tb_dataflow_core.v (M7, behavioral model widened to word-level) needed updates. The "real parallel scaling is flat beyond N_SLOTS=2" finding (DEC-0014) still holds - this optimization made the shared PSRAM port more efficient per transaction, not multi-ported - so N_SLOTS=2 remains the recommended default. Logged: simulation/synthesis/timing/benchmark/decisions (DEC-0015)/ experiments (EXP-0015)/development.log. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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3cdaeaee35 |
test(v2): final benchmark campaign - real end-to-end characterization (EXP-0014)
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 |
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micheleandClaude Sonnet 5
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91bbbe2fe5 |
feat(v2): M10 Optimization - data-driven findings, completes the V2 roadmap
Final milestone of docs/v2-description.md's §33 roadmap, scoped exactly to its own mandate: optimize only on data already gathered in M1-M9, across the pipeline/P_IN/processor-count/scheduling/memory axes - no speculative new features. Three concrete, data-driven results: 1. N_SLOTS=8 (numero processor axis): real synthesis + nextpnr-ecp5 P&R for dataflow_core at N_SLOTS=8, extending M7's N_SLOTS=2/4 sweep to the real DSP ceiling DEC-0005 predicted. 92.63 MHz POST-P&R, PASS at 80MHz, DSP 64/72 (88.9%). DEC-0012 recommends N_SLOTS=8 as the practical ceiling for P_IN=8 on the LFE5U-45F-8BG381. 2. ACC_WIDTH 24 vs 32 (pipeline axis): a real 6-seed nextpnr-ecp5 placement sweep (reusing already-synthesized netlists, no new synthesis needed) resolves EXP-0002's single-seed inconclusiveness. ACC_WIDTH=24 wins on both mean Fmax (+6.2%, 180.71 vs 170.12 MHz) and seed-to-seed variance (~3.4x tighter), on top of its already-known resource advantage. DEC-0013 recommends ACC_WIDTH=24 as the new default. 3. Stall %/utilization (scheduling/memory axes): testbench-only cycle counters added to tb_neural_multiprocessor.v (no RTL touched) close DEC-0011's deferred measurement gap with real data - shared PSRAM port 81.7% utilized, slot 0 95.2%, slot 1 65.2%, no conclusive evidence of harmful fixed-priority starvation at this scale. The 10-milestone V2 roadmap (docs/v2-description.md §33) is now complete end-to-end: real Verilator simulation, real Yosys synthesis, real nextpnr-ecp5 place & route for every milestone, fully logged (EXP-0001..EXP-0013, DEC-0001..DEC-0013, ERR-0001..ERR-0008) with no invented results (§30) and V1 kept frozen and untouched throughout (§1/§34). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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6cff2c8a7c |
feat(v2): M8 PSRAM integration - real V1 backend shared across concurrent slots
neural_multiprocessor.v wraps dataflow_core.v (M7, unmodified) around the real, unmodified V1 PSRAM backend chain (int8_memory_access -> memory_interface -> psram_controller), funneling N_SLOTS independent Memory Backend Interface ports through a new generic N-port arbiter (slot_mem_arbiter.v) inspired by (not copied from) V1's own mem_arbiter.v. Real concurrent-slot simulation immediately surfaced a genuine bug (ERR-0008): memory_manager/prefetch_engine's byte-level backend protocol is fire-and-forget (a single-cycle mem_req pulse with no accept handshake) - correct for M4's direct 1:1 connection, but a naive arbiter silently drops a pulse arriving while the shared bus is owned by another slot, hanging that slot forever. Fixed with a per-port pending-request latch, the same "queue, don't drop" idiom already used by memory_manager's own pf_pending register (ERR-0006). Verified (Verilator): 4/4 PASS with 2 slots genuinely contending for one real PSRAM port (444 cycles). No regression on M4's own testbench. Real synthesis + nextpnr-ecp5 P&R (no harness needed - real PSRAM pins keep the top-level at 157 pins): 0 problems, Fmax 142.45 MHz, PASS at 80MHz. Arbitration policy is fixed lowest-index priority, not fairness- balanced (DEC-0010) - consistent with every other "simplest correct policy first" scheduling choice in this roadmap, revisited only if M9's real measurement shows starvation matters. Logged: simulation/synthesis/timing/benchmark/decisions (DEC-0010)/ experiments (EXP-0009)/errors (ERR-0008)/development.log, ROADMAP.md updated. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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77baa8fc16 |
feat(v2): M7 Dataflow Core - full M1-M6 integration, wake-up loop closed end-to-end
dataflow_core.v integrates dependency_manager (M6) -> neural_director (M5) -> N_SLOTS x (memory_manager (M4) + neural_processor (M1)) for the first time. A slot's completion (via neural_director's new slot_node_id tracking, an additive port) feeds back as a producer_done event to dependency_manager, waking up any node that depended on it - closing the dataflow loop without external glue. Verified end-to-end (Verilator) on a 3-node DAG: two independent nodes plus a third depending on both, confirmed to dispatch only after both genuinely complete via real neural_processor computation. 4/4 PASS. Real synthesis + nextpnr-ecp5 P&R via a synthesis-only timing harness (bare per-slot backend ports exceed the LFE5U-45F's TRELLIS_IO budget, same pattern as ERR-0005): N_SLOTS=2 -> 165.15 MHz, N_SLOTS=4 -> 133.19 MHz, both PASS at 80MHz, 0 synthesis problems. Scope explicitly deferred to M8 (DEC-0009): M3's BRAM buffers not wired in yet, per-slot Memory Backend Interface ports not arbitrated to one shared PSRAM master yet - both need real measured data before committing to a design, not guessed at here. Logged: simulation/synthesis/timing/benchmark/decisions (DEC-0009)/ experiments (EXP-0008)/errors (ERR-0007, a Yosys chparam-ordering build quirk, not an RTL bug)/development.log, ROADMAP.md updated. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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8af16d3a12 |
feat(v2): M6 Dependency Manager, multi-dependency wake-up
Implements M6: dependency_manager.v tracks a table of node
descriptors (node_id/state/required_dependencies/resolved_
dependencies/producer_ids -- §10's exact field list), incrementing a
waiting node's resolved count whenever one of its listed producers
completes, transitioning it to READY once resolved==required, and
dispatching ready nodes to the Neural Director (M5) one at a time via
a backpressure-safe valid/ready interface.
Verified with Verilator on a small hand-built DAG: node0/node1 have no
dependencies (dispatch immediately); node2 depends on BOTH node0 AND
node1 ("dipendenze multiple") and stays WAITING until both complete,
confirmed via an explicit negative check after only one resolves;
node3 depends on node0 ALONE, demonstrating a single producer
("node0") satisfying two different consumers' dependencies
("risultati condivisi... piu' consumer") -- node3 fully, node2
partially. 4/4 tests pass.
Scope for this milestone (decisions.log DEC-0008): dependency
COUNTING/readiness only, no direct producer-to-consumer value
forwarding (§11 frames that as a "quando possibile" optimization, not
a correctness requirement -- deferred until real bandwidth
measurements justify it) and no node-slot reclamation after dispatch
(not exercised by any scenario built so far).
Real synthesis: 0 CHECK problems, 763 LUT4/474 FF/0 DSP/0 CCU2C. Real
place&route (module fits the TRELLIS_IO budget as a bare top-level
this time, no harness needed): Fmax 155.30 MHz, PASS at 80MHz.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
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micheleandClaude Sonnet 5
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2e4cedc761 |
feat(v2): M5 Neural Director, first-free job scheduling
Implements M5: neural_director.v dispatches job descriptors to whichever of N_SLOTS (memory_manager, neural_processor) pairs is currently free (first-free scheduling per §9's initial policy), with a parametric-depth ready-queue FIFO for jobs arriving faster than slots can absorb them. Scope for this milestone (see decisions.log DEC-0007): a reduced 4-state FSM (DIR_IDLE/SCAN_READY/ALLOCATE/ERROR) rather than §9's full 8-state baseline -- dependency tracking, the waiting queue, and wake-up are §10's explicit responsibility (Dependency Manager, M6, not yet built), and slot-completion detection runs as an always-active per-slot tracker rather than a dedicated FSM state, for the same reason DEC-0002 already gave for the Neural Processor's own FSM (gating concurrent per-unit progress behind one shared state kills throughput). Verified with Verilator (N_SLOTS=2, each slot backed by its own independent behavioral memory rather than sharing V1's real PSRAM -- M4 already proved that path for one slot; this milestone's own concern is scheduling across multiple slots): 4/4 tests pass -- 3 jobs submitted to 2 slots (first two dispatch immediately, third correctly queues until a slot frees), and a deliberate burst that forces the ready queue to genuinely fill and recover. Real synthesis: 0 CHECK problems, 382 LUT4/366 FF/4 CCU2C/0 DSP. Real place&route (via a synthesis-only timing harness, same TRELLIS_IO pin-budget reason as M2/M4): Fmax 250.50 MHz, PASS at 80MHz. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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175f697ae1 |
feat(v2): M4 Memory Manager + Prefetch Engine, real V1 PSRAM backend
Implements M4: memory_manager.v (arbitration/buffering/forwarding/ latency hiding/double buffering, §12) + prefetch_engine.v (double-buffered tile fetch, §13), sitting on the REAL, UNMODIFIED V1 PSRAM backend chain (int8_memory_access.v -> memory_interface.v -> psram_controller.v, per §15's explicit mandate not to touch the controller). Verified fully end-to-end with Verilator: real neural_processor (M1) fed entirely by memory_manager, computing against PSRAM-resident X/W tiles (double-buffered prefetch across up to 5 tiles) and writing its result back to PSRAM -- checked via an independent PSRAM read-back, with poison bytes around the operand regions to catch addressing errors. 3/3 jobs pass (1/3/5-tile configurations). Three real RTL bugs found and fixed during integration (full diagnostic trail in errors.log ERR-0006): prefetch_engine had no single-in-flight-request discipline, letting a queued request corrupt the bank bookkeeping of a fetch already running; the fix's own !pf_busy guard had a one-cycle blind spot (pf_busy lags pf_start by a clock) that needed an explicit !pf_start term; and a state-based mux for the shared backend port was off by one cycle, silently dropping the PSRAM result write entirely. Real synthesis: 0 CHECK problems, 851 LUT4/789 FF/108 CCU2C/0 DSP (expected, no multiplication in this module). Real place&route (via a synthesis-only timing harness, needed for the same TRELLIS_IO pin- budget reason as M2's array): Fmax 165.86 MHz, PASS at 80MHz. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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5f0d7f101c |
feat(v2): M3 activation/weight/result buffers, real BRAM mapping
Implements M3: three parametric dual-port buffers for the §12 data-plane (Input/Weight/Result), reusing the proven BRAM-inference idiom from the frozen hardware/v1/rtl/act_buffer.v (synchronous write, synchronous REGISTERED read, no reset on the read register -- keeps Yosys off the LUT-RAM path). Verified with Verilator: 10/10 tests pass (write-then-read correctness, extreme INT8 round-tripping, weight_buffer's full 64-bit tile width round-tripping, undisturbed re-reads). Real synthesis at two depths per module (6 configs total): 0 CHECK problems, every configuration correctly infers DP16KD (never LUT-RAM). Non-obvious real finding: weight_buffer's BRAM cost is driven by its P_IN*DATA_WIDTH tile width, not its DEPTH -- an 8x depth reduction (512->64) left DP16KD usage unchanged at 2, while activation_buffer/result_buffer (byte-wide) scale as naively expected (2->1). All default-depth configs PASS at 80MHz with large margin (287-367 MHz) via real nextpnr-ecp5 place&route. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |
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micheleandClaude Sonnet 5
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3026dcd997 |
feat(v2): M2 Neural Processor Array, N_PROCESSORS resource sweep
Implements M2 of the V2 roadmap: neural_processor_array.v instantiates
N_PROCESSORS independent neural_processor (M1) units, each with its
own dedicated point-to-point job/operand/result interface -- no shared
bus or mux at this level (arbitration is explicitly the Neural
Director's job, M5).
Verified with Verilator (tb_neural_processor_array.v, N_PROCESSORS=4):
7/7 tests pass, including a same-cycle 4-way concurrent launch with
different tile counts and a staggered-start test where a
later-launched, shorter job completes before an earlier-launched,
longer one -- confirming genuine independent concurrent execution
(§18/§34: a blocked/busy processor must not block the others).
Real resource/timing sweep for N_PROCESSORS in {1,2,4,8} (Yosys +
nextpnr-ecp5, real place&route): Fmax stays above the 80MHz target
throughout (159.11 -> 134.70 MHz), but MULT18X18D usage scales
linearly and reaches 88% of the LFE5U-45F's 72 DSPs at N=8 while
LUT/FF stay under 6% -- DSP, not LUT/FF/routing, is the first hard
ceiling on N_PROCESSORS at P_IN=8 (decisions.log DEC-0005). Measured
via a dedicated synthesis-only timing harness after the array's wide
per-processor buses were found to exhaust the device's TRELLIS_IO pin
budget as a bare top-level module beyond N=1 (errors.log ERR-0005) --
not a logic limit, an artifact of testing the array in isolation
before the Memory Manager/Director (M4/M5) exist to consume those
ports on-chip.
Full log trail (development/experiments/errors/decisions/simulation/
synthesis/timing/benchmark.log) in hardware/v2/logs/ per the project's
logging mandate.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
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micheleandClaude Sonnet 5
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dc0b331d3e |
feat(v2): scaffold hardware/v1 frozen baseline + M1 Neural Processor
Begins the V2 Neural Multiprocessor / Dataflow architecture per docs/v2-description.md, per explicit user request to freeze V1 and start V2 development, copying from V1 what's needed. Scaffold: - hardware/v1/: byte-exact, read-only copy of the current V1 codebase (rtl, testbenches, tools, constraints, a representative subset of synthesis results, and reference docs) -- verified identical via diff/cmp against the live top-level tree before being made filesystem-read-only. The live top-level tree is untouched and remains the project's "production" V1 (see hardware/v1/README.md and hardware/v2/logs/decisions.log DEC-0001 for why copy-not-move). - hardware/v2/: mandatory structure (rtl/sim/constraints/synthesis/ reports/scripts/logs/docs) plus the full logging system required by the spec (development/architecture/simulation/synthesis/timing/ benchmark/decisions/experiments/errors.log). M1 -- Neural Processor (hardware/v2/rtl/neural_processor.v): - 8-stage pipelined perceptron unit (P_IN=8): input align, 8 multipliers, 3-level adder tree, accumulator, bias+activation, INT8 saturation. Genuine 1-tile/cycle throughput, not just a wider combinational datapath. - 7-state FSM (NP_IDLE..NP_ERROR per docs/v2-description.md §6, with 4 baseline states merged into NP_WAIT_OPERANDS -- see decisions.log DEC-0002); valid/ready/data/last stream interfaces per §7. - Bit-exact vs the frozen hardware/v1/rtl/neuron_parallel.v + mac8.v + mac_unit.v: 7/7 tests pass (hardware/v2/sim/tb_neural_processor.v), covering regular/mixed-sign/extreme-INT8 vectors, both activations, a zero-idle-gap back-to-back-tiles throughput check, and an 8-tile job -- verified with Verilator (see below for why). - Real synthesis + place&route (Yosys + nextpnr-ecp5): 0 CHECK problems, Fmax 183.12 MHz at ACC_WIDTH=32 (PASS at 80MHz, ~3x V1's isolated PARALLEL=8 Fmax of 61.71 MHz) and 176.21 MHz at ACC_WIDTH=24 (a user-requested comparison experiment, also bit-exact-verified; see experiments.log EXP-0001/EXP-0002 and benchmark.log). Three real bugs found and resolved during M1 development (full diagnostic record in errors.log): - Two independent, reproducible Icarus Verilog v13.0 scheduling defects (ERR-0001, ERR-0002) that silently produced wrong simulation results for standard sequential Verilog -- confirmed via Verilator 5.050 giving correct results on the same minimal repros. Verilator is now the trusted simulator for hardware/v2/ (decisions.log DEC-0004); Icarus's affected protocol-violation check was removed from the RTL and deferred architecturally to the Neural Director (DEC-0003) rather than chased further. - One real RTL bug (ERR-0003): last0 wasn't gated like valid0, letting a "last tile" tag leak into the pipeline ahead of its actual valid tile on back-to-back jobs. Fixed and verified. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v |