osobhandClaude Opus 5.5
b55b24b7ba
Every crate under crates/ now has a README (android, bench, cli, napi and wasm had none), each saying what the crate is, its main types and functions (names checked against the code), its cargo features with defaults and which ones build C (checked with `cargo tree`), and links to the top-level docs. Corrections to the old stubs: - clawhdf5-derive: the derive is `H5Type`, not `HDF5Type`, and it needs clawhdf5-format as a dependency. - clawhdf5-filters: deflate backends only, and no library crate depends on it; the filter pipeline and every other codec are in -format. - clawhdf5-gpu: vector distance compute, not I/O; not used by HDF5Memory::search. - clawhdf5-io: MpiVol is root-read + broadcast, not collective MPI-IO. - clawhdf5-ann: from_hdf5/search(q, k) did not exist; load_from_hdf5 and search(q, k, ef). - clawhdf5-accel: checksum::crc32_simd did not exist; the SSE4 and wasm backends are reported but run the scalar kernels. - clawhdf5-gpu: the old example called l2_distances, which does not exist (l2_search). - clawhdf5-agent: it described a "vector store" with "GPU acceleration"; it now covers HDF5Memory, search options, WAL, signing, the graph. - crates.io/docs.rs badges removed and `cargo install <crate>` replaced: nothing is published; depend on git. - fuzz: the opt-in CLAWHDF5_FUZZ_SECONDS smoke run in ci-test.sh. - tools: the FileEditor interop tests that live in this crate. - remote, py: license, other front ends, limits, File.mode/flush/chunks. The Rust examples of the facade, format, filters, accel, ann, derive and agent READMEs were compiled and run as tests (netcdf4, gpu and remote compiled only) in a scratch crate; the CLI example was run. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
56 lines
2.6 KiB
Markdown
56 lines
2.6 KiB
Markdown
# clawhdf5-io
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I/O building blocks under [`clawhdf5`](../clawhdf5/README.md): the
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`HDF5Read`/`HDF5ReadWrite` traits with in-memory, borrowed, file and
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memory-mapped readers, plus several experimental modules (async reads, an
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HSDS client, a VOL-style trait, sub-filing, prefetch, and an MPI connector).
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The facade uses it for memory-mapped reads (`MmapReader`, and the private
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copy-on-write mapping that applies a metadata cache image).
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Remote files are **not** read through this crate: HTTP(S) and object
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stores go through `clawhdf5_format::storage::Storage` and
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[`clawhdf5-remote`](../clawhdf5-remote/README.md).
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Not on crates.io yet; depend on it from git:
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```toml
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[dependencies]
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clawhdf5-io = { git = "https://git.redclaw.dev/quantumclaw/clawhdf5", features = ["mmap"] }
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```
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## Main items
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| Item | What |
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| `HDF5Read`, `HDF5ReadWrite` | byte-level read/write traits; `MemoryReader`, `BorrowedReader`, `FileReader`, `FileWriter` implement them |
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| `MmapReader`, `MmapReadWrite` (`mmap`) | memory-mapped files through `memmap2`; `HDF5Read::private_copy` gives a copy-on-write view |
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| `prefetch::PrefetchReader`, `sweep::SweepDetector` | read-ahead (`madvise(MADV_WILLNEED)` on mappings) and chunk-sweep prediction |
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| `ParallelConfig` | lane partitioning for parallel chunk decoding |
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| `vol::VirtualObjectLayer`, `vol::NativeVol` | a backend-agnostic object-layer trait (modelled on libhdf5's VOL) |
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| `async_read` (`async`) | tokio-based `AsyncHDF5Read` and `AsyncHDF5File` |
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| `hsds::HsdsClient` (`hsds`) | a REST client for an HSDS server |
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| `subfiling` | splitting one logical file across several physical files |
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| `mpi_vol::MpiVol` (`mpi-io`) | an MPI connector: see below |
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### MPI (`mpi-io`)
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`MpiVol` is **not collective MPI-IO**. Reads are root-read + broadcast
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(rank 0 reads the file with `std::fs::read`, parses the dataset and
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broadcasts the bytes); writes gather every rank's shard to rank 0, which
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writes the merged dataset. It does not call `MPI_File_read_at_all` or any
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other MPI-IO routine. Collective I/O is on the [roadmap](../../ROADMAP.md).
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`clawhdf5-bench`'s `mpi_io_bench` binary exercises it.
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## Features
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| Feature | Default | What | Builds C |
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| `mmap` | no (the `clawhdf5` facade turns it on) | `MmapReader`, `MmapReadWrite` | no |
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| `async` | no | `async_read` (tokio) | no |
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| `hsds` | no | `hsds` (reqwest, and `async`) | yes: reqwest's default TLS is native-tls (OpenSSL on Linux) |
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| `mpi-io` | no | a real `MpiVol` (without it `MpiVol::new_world` returns an error) | yes: `mpi-sys` needs an MPI installation and libclang |
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## License
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MIT
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