- README's "HDF5 Core I/O" table claimed 19ns/2,080µs labeled 308× (real ratio
~109,000×) and a 313ns zero-copy mmap figure — neither traced to any dated
benchmark in BENCHMARKS.md. Replaced the table wholesale with the existing
"vs libhdf5 Summary" figures, relabeled from "h5py/C HDF5" to "libhdf5"
(BENCHMARKS.md never benchmarks against h5py, only libhdf5 directly).
- Added two new Criterion benchmarks to close the coverage gaps that produced
the untraceable numbers: metadata_open_from_disk (I/O-inclusive, fair
clawhdf5-vs-libhdf5 file-open comparison) and metadata_parse_in_memory
(clawhdf5-only, explicitly labeled as excluding I/O) in h5bench_meta.rs;
read_zerocopy_mmap in h5bench_read.rs (forces real page-ins by summing
elements rather than just returning a slice length — the mmap path turns
out to be slower than a plain copy at these sizes, an honest, unflattering
but real result now documented instead of a fabricated 313ns).
- Re-ran the full existing benchmark suite plus the two new ones on a second,
independently administered machine (tank: Ryzen 7 7800X3D) to validate the
numbers before publishing them. 5 of 6 rows landed within ~15% of the
original i7-12650H figures; recorded both in BENCHMARKS.md's new
"Independent Validation" section. README now cites the tank numbers.
- Added a short top-of-file README callout naming both halves of the project
(general-purpose HDF5 library vs. agent memory layer) with links to
BENCHMARKS.md and the Crate Map, so a data-infra reader isn't 60% through
a memory-store pitch before finding the part relevant to them.
- Added one factual, no-names line noting benchmark numbers are being
validated in collaboration with HDF5 Group engineers.
- Fixed the same untraceable "2-300x faster than h5py/C HDF5" / "313 ns"
claims in docs/QUICKSTART.md, one click from the README's own "New here?"
link.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Implements Pcodec (filter ID 32023) via the `pco` 1.0.x crate as a new
optional compression codec. Pcodec achieves 30–94% better compression
ratio than Zstd for f32/f64 columnar data at 1–5 GiB/s decompression
speed, making it ideal for write-once/read-many embedding archives.
Write throughput at 512×512: 591 MiB/s (parity with Zstd-3 at 610 MiB/s).
For smaller chunks Zstd-3 remains faster due to Pcodec's fixed per-chunk
distributional analysis overhead.
- Add FILTER_PCODEC = 32023 constant to filter_pipeline.rs
- Add pcodec_compress/pcodec_decompress using pco::standalone API
- Wire into compress_chunk/decompress_chunk dispatch
- Add ChunkOptions.pcodec field and DatasetBuilder.with_pcodec() method
- Enable pcodec as highest-priority codec in build_pipeline()
- Add pco dep (optional, feature = "pcodec") to clawhdf5-format/clawhdf5
- Add write_2d_chunked_pcodec benchmark comparing pcodec vs zstd-3
- Document results in BENCHMARKS.md
Co-Authored-By: Claude Sonnet 4.6 <[email protected]>
Add features = ["zstd"] to clawhdf5-bench dev-dependency so the
write_2d_chunked_zstd benchmark no longer panics with UnsupportedFilter(32015).
Update BENCHMARKS.md and README.md with measured results from the full
h5bench write suite (2026-06-30, post write-performance improvements):
- Zstd-3 hits 593 MiB/s at 512×512 vs deflate-6's 280 MiB/s (2.12×)
- Zstd-3 hits 330 MiB/s at 128×128 vs deflate-6's 132 MiB/s (2.51×)
- Sequential f64 batch write improved ~8-11% from owned-Vec IO path
Co-Authored-By: Claude Sonnet 4.6 <[email protected]>
Four independent write-path improvements:
1. Cache compressed chunks between Pass 1 and Pass 2 (chunked_write.rs,
file_writer.rs): the two-pass layout writer previously called
build_chunked_data_at_ext() twice per chunked dataset — once in Pass 1
to get blob sizes and once in Pass 2 with real addresses. Add
PrecompressedChunks / precompress_chunks() / build_chunked_data_from_
precompressed() to compress once in Pass 1, cache the result, and only
rebuild the address-dependent index structures in Pass 2. Expected
~2× speedup for chunked+deflate writes (512×512 deflate: 3.33ms → ~1.7ms).
2. SIMD-vectorisable shuffle filter (filters.rs): replace the naïve O(N·S)
nested loop with an unrolled u32-load path for 4-byte elements (f32) and
a cache-blocked tile loop for all other sizes. LLVM auto-vectorises the
4-byte path into SSE2/AVX2/NEON byte-deinterleave sequences.
3. Zstd benchmark variant (h5bench_write.rs): add write_2d_chunked_zstd
group measuring Zstd level 3 vs deflate level 6 side-by-side. Also fix
the existing write_2d_chunked benchmark — the clawhdf5 path was missing
.with_deflate(6), making the comparison apples-to-oranges. Add arXiv-
backed doc recommendation on DatasetBuilder::with_zstd().
4. Zero-copy HNSW save (hnsw.rs, clawhdf5-io/lib.rs): add
FileWriter::write_bytes_owned(Vec<u8>) that takes ownership to avoid the
full-file clone in write_all_bytes(&[u8]). HNSW::save_to_hdf5 uses it.
Co-Authored-By: Claude Sonnet 4.6 <[email protected]>
Adds three Criterion benchmark suites mirroring the h5bench HPC I/O
benchmark workloads in pure Rust — no C libhdf5 required for the default
path, with an optional `libhdf5-compare` feature for side-by-side numbers.
- benches/h5bench_write.rs: write_1d_contiguous, write_2d_chunked,
write_f64_batch, write_multi_dataset, write_with_attrs
- benches/h5bench_read.rs: read_sequential, read_f64_sequential,
read_chunked_2d, read_from_disk, read_hyperslab
- benches/h5bench_meta.rs: metadata_attrs_write, metadata_attrs_read,
metadata_groups_create, metadata_groups_traverse, metadata_string_attrs
All benchmarks pass `cargo bench --bench <name> -- --test` and clippy
reports zero warnings. Run with `cargo bench -p clawhdf5-bench`.
Co-Authored-By: Claude Sonnet 4.6 <[email protected]>
Bumps [workspace.package] and all 17 crate package versions (and internal
path-dependency requirements) from 2.0.0 to 2.1.0 for a coordinated release.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
