The S-expression wire format was the bottleneck at huge payload sizes
-- 23.8 s end-to-end for 1M x 16 B inputs on the Python tier, while
the actual CUDA kernel finishes the same workload in ~47 ms. The
hex-S-exp parser ate everything between.
New binary wire mode (magic 'BSHK' prefix; payload is the daemon's
binary portal format verbatim) bypasses S-expression parsing entirely.
Worker writes the blob to disk, calls daemon process-bin, reads result,
prepends 'BSHR' magic, replies.
Measured 3090-ai, daemon warm, localhost:
workload Py S-exp Py binary C S-exp C binary
100 x 16 B 3.43 ms 0.74 ms 0.40 ms 0.15 ms
1k x 16 B 23.24 ms 0.76 ms 2.77 ms 0.22 ms
10k x 16 B 218.82 ms 1.27 ms CLIFF 0.88 ms
100k x 16 B 2,219 ms 10.18 ms CLIFF 10.35 ms
1M x 16 B 23,811 ms 159 ms CLIFF 157 ms
150x speedup at 1M inputs on Python tier. C tier S-exp CLIFFs
between 1k and 10k inputs (reader payload limit); binary mode
bypasses the CLIFF entirely. At 100k+ inputs both tiers converge
since file I/O + CUDA kernel dominates over wire framing.
Host comparison: hashlib.shake_256 over 1M tiny inputs takes ~2 s
on a single Python core. Bend via binary worker = 157 ms = 12x
faster than host. Bend now wins at huge workloads, not just heavy
ones.
Implementation:
lumbda.py
* tcp-send/tcp-recv switched to latin-1 (1:1 byte mapping)
so binary payloads pass through cleanly. UTF-8 was mangling
bytes with replacement chars.
* write-binary-file / read-binary-file primitives.
c/builtins.c
* write-binary-file / read-binary-file matching Python tier.
examples/cuda-fanout/wire.lsp
* wire-send-raw / wire-recv-raw helpers that frame a raw
payload string without S-expression serialization.
examples/cuda-fanout/gpu-worker.lsp
* handle-binary-shake: write portal blob, daemon process-bin,
read result, wire-send 'BSHR' + bytes.
* handle-one dispatches on first 4 bytes of payload: 'BSHK'
goes to binary path, anything else stays S-exp.
examples/cuda-fanout/bench_tiers.py
* make_payload_binary builds the BSHK protocol payload.
* --binary flag in CLI.
www/index.html
* full S-exp + binary comparison table.
* 'bend now beats host hashlib at huge workloads' headline finding.
russell@unturf.com
01ea93f68f
