50 lines
2.0 KiB
Markdown
50 lines
2.0 KiB
Markdown
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# Benchmarking
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How the nfs project is measured. Every number a document, a README or a changelog
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quotes comes from here and nowhere else.
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## The method
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- Two levels are measured, and they answer different questions. The backend level
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benchmarks the `internal/nfsfs` filesystem layer on its own: what one READ, WRITE,
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GETATTR or LOOKUP costs against a local directory. The wire level benchmarks whole
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NFS sessions: the server binary and the client library over a loopback connection,
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which adds the RPC, XDR and session layers on top of the backend.
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- What is deliberately left out: kernel NFS mounts, the network beyond loopback, and
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any comparison against other NFS servers. Those are interop questions, not
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benchmark questions.
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- The machine is idle, named, and stays the same across comparable reports.
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- The toolchain is named with its version and its build flags.
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- Comparisons run inside one process, with the order of the two sides alternated
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where a comparison is the point. Differences under two percent are noise, not
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results.
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- A change is measured against its baseline, not against a memory of how fast it
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used to be. The baseline run is part of the measurement, and both sides land in
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the same report.
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## Running
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```sh
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just bench
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```
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The recipe sweeps `./internal/...` with `-benchmem -count=5`.
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A first look at one target, before the full battery is worth the time:
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```sh
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go test -run '^$' -bench 'BenchmarkRead64K' -benchtime=1x ./internal/nfsfs
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```
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The full battery runs once, deliberately, on an idle machine. A benchmark command
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is capped at about two minutes per round; longer sweeps are split.
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## Reports
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Reports live in `docs/_results/`, one file per measurement round, named
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`YYYY-MM-DD-subject.md`, and follow [BENCHMARK_TEMPLATE.md](BENCHMARK_TEMPLATE.md).
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A report carries its numbers, its machine, its toolchain and the exact command. A
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number without its provenance is not a result, and a performance claim without a
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report behind it is left out of the documentation rather than softened into an
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adjective.
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