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perf: vectorize small u8 table take with NEON - #9571
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Merging this PR will improve performance by ×9.6
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| Mode | Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|---|
| ⚡ | WallTime | dict_canonicalize_gt_u8_neon[1000000] |
487.8 µs | 50.9 µs | ×9.6 |
| Simulation | density_sweep_dense_runs[0.9] |
< 1 ns | < 1 ns | N/A |
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Comparing ji/small-u8-table-take-neon (544409f) with develop (98e9ff4)
Footnotes
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518 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
Use NEON TBL for u8-coded tables with at most 16 one-byte values. Signed-off-by: Joseph Isaacs <joseph-isaacs@users.noreply.github.com>
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`take_small_byte_table_rejects_out_of_bounds_index` asserts the NEON small-table bounds-check message, but the table path only exists on little-endian AArch64. On other targets `take_values` falls through to the AVX2 or scalar path, whose panic messages differ, so the test failed on the linux-musl runner (no AVX2: the scalar path panics with the plain slice message). Gate the test on the same cfg as the module. `take_small_byte_table` stays unconditional so every target keeps checking the results. DCO Remediation Commit for Joe Isaacs <joe.isaacs@live.co.uk> I, Joe Isaacs <joe.isaacs@live.co.uk>, hereby add my Signed-off-by to this commit: e97db31 Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk> Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013YND3Jq47YtL15ob3GEsVY
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…take-neon Picks up #9819, which fixes the `VarBinBuilder::with_capacity` deprecation in `vortex-btrblocks` that was failing both `Rust (lint)` jobs on this PR. Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk>
robert3005
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Sep 16, 2026
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| let mut table = [0u8; 16]; | ||
| // SAFETY: one-byte values have the same representation as bytes, and the length is <= 16. | ||
| unsafe { | ||
| std::ptr::copy_nonoverlapping( | ||
| values.as_ptr().cast::<u8>(), | ||
| table.as_mut_ptr(), | ||
| values.len(), | ||
| ); | ||
| } |
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can this use a safe conversion? This seems like an overkill
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| unsafe { | ||
| output_ptr | ||
| .add(offset) | ||
| .write(*values.as_ptr().add(code).cast::<u8>()) | ||
| }; | ||
| } |
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I think you can replace this with write_copy_of_slice
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or just write? This seems weird to have the assert above and then unsafe here.
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This PR has been marked as stale because it has been open for 14 days with no activity. Please comment or remove the stale label if you wish to keep it active, otherwise it will be closed in 7 days |
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Benchmarks: String Encoding 📖Commits: PR vortex / vortex-file-compressed / ms (0.998x ➖, 0↑ 0↓)
vortex / vortex-file-compressed / % (1.000x ➖, 0↑ 0↓)
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Polar Signals Profiling ResultsLatest Run
Previous Runs (14)
Powered by Polar Signals Cloud |
Contributor
Benchmarks: PolarSignals Profiling 📖Commits: PR datafusion / vortex-file-compressed / ns (0.983x ➖, 0↑ 0↓)
File Size Changes (1 files changed, +8.6% overall, 1↑ 0↓)
Totals:
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Contributor
Benchmarks: FineWeb NVMe 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.021x ➖, 2↑ 2↓)
datafusion / vortex-compact / ns (1.120x ❌, 0↑ 3↓)
datafusion / parquet / ns (1.052x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (1.026x ➖, 2↑ 3↓)
duckdb / vortex-compact / ns (0.966x ➖, 2↑ 1↓)
duckdb / parquet / ns (1.022x ➖, 0↑ 1↓)
File Size Changes (2 files changed, +13.9% overall, 1↑ 1↓)
Totals:
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Contributor
Benchmarks: TPC-H SF=1 on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (0.997x ➖, 0↑ 0↓)
datafusion / vortex-compact / ns (1.007x ➖, 0↑ 0↓)
datafusion / parquet / ns (1.001x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (1.007x ➖, 1↑ 2↓)
duckdb / vortex-compact / ns (1.001x ➖, 0↑ 1↓)
duckdb / parquet / ns (0.992x ➖, 0↑ 0↓)
File Size Changes (16 files changed, +10.3% overall, 11↑ 5↓)
Totals:
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Contributor
Benchmarks: Clickbench Sorted on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (0.729x ✅, 10↑ 0↓)
datafusion / vortex-compact / ns (1.014x ➖, 0↑ 0↓)
datafusion / parquet / ns (1.010x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (0.738x ✅, 8↑ 1↓)
duckdb / vortex-compact / ns (0.979x ➖, 1↑ 1↓)
duckdb / parquet / ns (0.954x ➖, 0↑ 0↓)
File Size Changes (200 files changed, +15.0% overall, 134↑ 66↓)
Totals:
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Contributor
Benchmarks: Compression 📖Commits: PR vortex / vortex-file-compressed / ns (0.956x ➖, 5↑ 0↓)
vortex / vortex-file-compressed / bytes (1.023x ➖, 0↑ 3↓)
vortex / vortex-file-compressed / ratio (0.975x ➖, 5↑ 3↓)
vortex / parquet / ns (1.004x ➖, 0↑ 0↓)
vortex / parquet / bytes (1.000x ➖, 0↑ 0↓)
vortex / arrow-ipc / ns (1.010x ➖, 0↑ 1↓)
vortex / arrow-ipc / bytes (1.000x ➖, 0↑ 0↓)
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Contributor
Benchmarks: FineWeb S3 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.135x ➖, 1↑ 4↓)
datafusion / vortex-compact / ns (0.971x ➖, 1↑ 1↓)
datafusion / parquet / ns (1.067x ➖, 1↑ 1↓)
duckdb / vortex-file-compressed / ns (1.059x ➖, 0↑ 1↓)
duckdb / vortex-compact / ns (0.968x ➖, 1↑ 0↓)
duckdb / parquet / ns (1.076x ➖, 0↑ 1↓)
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Contributor
Benchmarks: Appian on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-compact / ns (0.998x ➖, 0↑ 0↓)
datafusion / parquet / ns (0.998x ➖, 0↑ 0↓)
duckdb / vortex-compact / ns (0.994x ➖, 0↑ 0↓)
duckdb / parquet / ns (0.991x ➖, 0↑ 0↓)
File Size Changes (9 files changed, +0.0% overall, 2↑ 7↓)
Totals:
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Contributor
Benchmarks: Statistical and Population Genetics 📖Commits: PR How to read Verdict and Engines
duckdb / vortex-file-compressed / ns (0.875x ✅, 5↑ 0↓)
duckdb / vortex-compact / ns (1.013x ➖, 0↑ 0↓)
duckdb / parquet / ns (0.980x ➖, 1↑ 0↓)
File Size Changes (2 files changed, +10.4% overall, 1↑ 1↓)
Totals:
|
Contributor
Benchmarks: TPC-H SF=10 on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (0.992x ➖, 0↑ 0↓)
datafusion / vortex-compact / ns (0.993x ➖, 0↑ 0↓)
datafusion / parquet / ns (1.010x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (0.992x ➖, 1↑ 0↓)
duckdb / vortex-compact / ns (0.993x ➖, 0↑ 0↓)
duckdb / parquet / ns (0.995x ➖, 0↑ 0↓)
File Size Changes (16 files changed, +10.5% overall, 10↑ 6↓)
Totals:
|
Contributor
Benchmarks: TPC-DS SF=1 on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.010x ➖, 0↑ 3↓)
datafusion / vortex-compact / ns (1.007x ➖, 0↑ 1↓)
datafusion / parquet / ns (1.006x ➖, 1↑ 0↓)
duckdb / vortex-file-compressed / ns (0.983x ➖, 6↑ 5↓)
duckdb / vortex-compact / ns (1.004x ➖, 1↑ 1↓)
duckdb / parquet / ns (0.998x ➖, 2↑ 1↓)
File Size Changes (48 files changed, +1.6% overall, 23↑ 25↓)
Totals:
|
Contributor
Benchmarks: Clickbench on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (0.897x ✅, 13↑ 1↓)
datafusion / vortex-compact / ns (1.004x ➖, 0↑ 0↓)
datafusion / parquet / ns (1.029x ➖, 0↑ 1↓)
duckdb / vortex-file-compressed / ns (0.941x ➖, 15↑ 2↓)
duckdb / vortex-compact / ns (1.004x ➖, 0↑ 0↓)
duckdb / parquet / ns (1.020x ➖, 0↑ 4↓)
File Size Changes (200 files changed, +17.7% overall, 145↑ 55↓)
Totals:
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Contributor
Benchmarks: TPC-H SF=1 on S3 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.030x ➖, 0↑ 3↓)
datafusion / vortex-compact / ns (0.953x ➖, 1↑ 3↓)
datafusion / parquet / ns (0.942x ➖, 2↑ 0↓)
duckdb / vortex-file-compressed / ns (1.159x ➖, 0↑ 3↓)
duckdb / vortex-compact / ns (0.974x ➖, 0↑ 1↓)
duckdb / parquet / ns (1.033x ➖, 0↑ 0↓)
|
Contributor
Benchmarks: TPC-H SF=10 on S3 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-compact / ns (1.048x ➖, 2↑ 7↓)
datafusion / parquet / ns (1.007x ➖, 1↑ 2↓)
duckdb / vortex-compact / ns (1.188x ➖, 0↑ 4↓)
duckdb / parquet / ns (1.178x ➖, 0↑ 6↓)
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Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk>
Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk>
Contributor
Benchmarks: Random Access 📖Commits: PR How to read Verdict and Engines
vortex / arrow-ipc / ns (1.002x ➖, 7↑ 2↓)
random-access / vortex-file-compressed / ns (0.970x ➖, 3↑ 1↓)
random-access / parquet / ns (1.030x ➖, 0↑ 1↓)
random-access / lance / ns (0.993x ➖, 0↑ 0↓)
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Signed-off-by: Joe Isaacs <joe.isaacs@live.co.uk>
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Benchmarks: PolarSignals Profiling 📖Commits: PR datafusion / vortex-file-compressed / ns (1.001x ➖, 0↑ 0↓)
No file size changes detected. |
Contributor
Benchmarks: FineWeb NVMe 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.010x ➖, 0↑ 1↓)
datafusion / parquet / ns (0.996x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (1.005x ➖, 2↑ 3↓)
duckdb / parquet / ns (0.997x ➖, 0↑ 0↓)
No file size changes detected. |
Contributor
Benchmarks: TPC-H SF=1 on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (0.998x ➖, 0↑ 0↓)
datafusion / parquet / ns (0.999x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (0.991x ➖, 1↑ 0↓)
duckdb / parquet / ns (1.010x ➖, 0↑ 1↓)
No file size changes detected. |
Contributor
Benchmarks: TPC-DS SF=1 on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (0.999x ➖, 1↑ 0↓)
datafusion / parquet / ns (1.000x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (0.997x ➖, 2↑ 3↓)
duckdb / parquet / ns (0.997x ➖, 2↑ 1↓)
No file size changes detected. |
Contributor
Benchmarks: TPC-H SF=10 on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.005x ➖, 0↑ 0↓)
datafusion / parquet / ns (1.001x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (0.987x ➖, 1↑ 0↓)
duckdb / parquet / ns (1.001x ➖, 0↑ 0↓)
No file size changes detected. |
Contributor
Benchmarks: Clickbench on NVME 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.004x ➖, 0↑ 0↓)
datafusion / parquet / ns (1.000x ➖, 0↑ 0↓)
duckdb / vortex-file-compressed / ns (0.992x ➖, 1↑ 2↓)
duckdb / parquet / ns (0.983x ➖, 2↑ 0↓)
No file size changes detected. |
Contributor
Benchmarks: TPC-H SF=1 on S3 📖Commits: PR How to read Verdict and Engines
datafusion / vortex-file-compressed / ns (1.011x ➖, 0↑ 2↓)
datafusion / parquet / ns (0.938x ➖, 2↑ 0↓)
duckdb / vortex-file-compressed / ns (0.977x ➖, 1↑ 0↓)
duckdb / parquet / ns (0.982x ➖, 0↑ 0↓)
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Rationale
Low-cardinality dictionaries with
u8codes and one-byte values can decode through an in-register NEON table instead of arbitrary scalar lookups.Stacked on benchmark baseline #9566. The x86 implementation is intentionally split into the next PR.
Changes
TBLon little-endian AArch64.u8codes, at most 16 one-byte values, and at least 64 rows.CodSpeed wall-time results
Medians over 1,000 samples on Graviton3 metal, compared with #9566:
Runs: baseline, optimized.
Checks
cargo +nightly fmt --all --checkgit diff --check