CRC checksums (CRC-16, CRC-32, CRC-32C) for OCaml
Add CRC benchmarks, software-only API, and update README
Add bench/ with throughput comparison of the three implementation tiers:
- Byte-at-a-time (reference baseline): ~290 MB/s
- Slicing-by-8 (software fast path): ~730 MB/s
- Hardware ARM CRC intrinsics: ~12-16 GB/s
Expose crc32_software / crc32c_software for benchmarking and testing
the software path independently of hardware dispatch.
Update README to document performance tiers, hardware detection, and
portability story (jsoo/wasm).
+6
-9
+6
-9
bench/bench.ml
+6
-9
bench/bench.ml
···
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let crc = ref 0xFFFFFFFFl in
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for i = 0 to String.length data - 1 do
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let byte = Int32.of_int (Char.code (String.unsafe_get data i)) in
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-
let idx =
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-
Int32.to_int (Int32.logand (Int32.logxor !crc byte) 0xFFl)
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-
in
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+
let idx = Int32.to_int (Int32.logand (Int32.logxor !crc byte) 0xFFl) in
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crc :=
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-
Int32.logxor crc32c_table_simple.(idx)
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-
(Int32.shift_right_logical !crc 8)
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+
Int32.logxor crc32c_table_simple.(idx) (Int32.shift_right_logical !crc 8)
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done;
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Stdlib.(Int32.to_int (Int32.logxor !crc 0xFFFFFFFFl) land 0xFFFFFFFF)
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···
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let elapsed = Unix.gettimeofday () -. t0 in
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let bytes_total = Float.of_int (String.length data * iterations) in
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let throughput_mbs = bytes_total /. elapsed /. 1_000_000.0 in
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Printf.printf " %-28s %8.1f MB/s (%d iters in %.3fs)\n" name
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-
throughput_mbs iterations elapsed
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+
Printf.printf " %-28s %8.1f MB/s (%d iters in %.3fs)\n" name throughput_mbs
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+
iterations elapsed
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let run_suite ~label ~sizes =
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Printf.printf "\n=== %s ===\n" label;
···
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Printf.printf "\n --- %d bytes (%d iterations) ---\n" size iterations;
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measure_throughput ~name:"byte-at-a-time" ~f:crc32c_byte_at_a_time ~data
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~iterations;
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measure_throughput ~name:"slicing-by-8 (software)"
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~f:Crc.crc32c_software ~data ~iterations;
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+
measure_throughput ~name:"slicing-by-8 (software)" ~f:Crc.crc32c_software
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+
~data ~iterations;
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measure_throughput ~name:"auto (hw if available)" ~f:Crc.crc32c ~data
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~iterations)
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sizes