chore(bench): move specifier allocation out of the timed symlink loop#1270
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The two "resolve from symlinks" benches allocated 10k `format!` strings and ran an `assert!` branch inside the timed body, unlike the sibling benches which iterate precomputed data and discard results. Precompute the specifiers once (also reusing a single resolver for the pre-bench validation pass instead of constructing 10k of them). Note: this removes allocation noise from the measurement, so the CodSpeed series for resolver_memory/resolve-from-symlinks and resolver_real/resolve-from-symlinks will step down.
Merging this PR will improve performance by 4.08%
|
| Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|
| ❌ | pm/pnpm-isolated |
1 ms | 1.1 ms | -5.3% |
| ⚡ | resolver_memory[resolve from symlinks] |
25.7 ms | 23.5 ms | +9.21% |
| ⚡ | resolver_real[resolve from symlinks] |
25.6 ms | 23.6 ms | +8.58% |
| ⚡ | pm/bun-isolated |
1.1 ms | 1 ms | +4.58% |
| ⚡ | pm/yarn-flat |
992.1 µs | 954 µs | +3.99% |
Tip
Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.
Comparing chore/bench-symlink-specifiers (a000405) with main (0fbd4a3)
Footnotes
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5 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. ↩
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The two "resolve from symlinks" benches did, per timed iteration, 10,000 eager
format!("./file{i}")allocations plus anassert!(.. .is_ok())branch — unlike every sibling bench in the file, which iterates precomputed data and discards results with_ =. The asserts also re-checked an invariant already validated once before the benchmark group runs.This precomputes the specifiers once (mirroring the
find tsconfigbench's hoisting pattern) and drops the in-loop asserts, so the benches measure symlink resolution rather than resolution + allocation noise. The validation pass also now constructs one resolver instead of 10,000.Heads-up: this will step-change the CodSpeed series for
resolver_memory/resolve from symlinksandresolver_real/resolve from symlinksdownward — that's the removed allocation/assert overhead, not a resolver perf change.Part of a second cleanup pass; follows #1264–#1268.