28 lines
1.1 KiB
Markdown
28 lines
1.1 KiB
Markdown
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# Measurement: the paginated READDIR
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- Date: 2026-09-22
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- Machine: AMD Ryzen AI Max+ Pro 395 (32 threads), otherwise idle
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- Toolchain: go1.27.1, no build flags
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- Command: `go test ./internal/nfsfs/ -run '^$' -bench=ReadDirPage -benchmem -count=1 -benchtime=50x`
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## Baseline
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The commit 340783e, measured in the same session as the new code. The
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benchmark pages a 10 000 entry directory 64 entries at a time, which is the
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shape of a client listing a large directory through READDIR pages: the
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baseline re listed and re sorted the whole directory for every page.
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## Result
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Median free, 50 iterations per side, one session.
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| Benchmark | Baseline | With the listing cache | Change |
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|---|---|---|---|
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| `BenchmarkReadDirPage64` | 1863611 ns/op, 1402 KiB/op, 20290 allocs/op | 62506 ns/op, 40 KiB/op, 267 allocs/op | -96.6 % |
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A page of 64 costs 30 times less once the sorted order is cached and
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revalidated against the directory's modification time, and the cost no
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longer grows with the size of the directory: the numbers above are the
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boundary case, where a page paid for listing and sorting ten thousand names
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to serve sixty four of them.
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