New browser instance per benchmark task#808
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pgarrison
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May 28, 2026
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| @@ -14,14 +12,6 @@ function setStatus(msg: string) { | |||
| console.log("[benchmark]", msg); | |||
| } | |||
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| // Nearest-rank percentile over a pre-sorted array. Used to report p50 and p95 | |||
| // across timed iterations — p95 surfaces occasional slow outliers (GC pauses, | |||
| // DuckDB cache misses) that the median would hide. | |||
| function percentile(sorted: number[], p: number): number { | |||
| const idx = Math.ceil((p / 100) * sorted.length) - 1; | |||
| return sorted[Math.max(0, idx)]; | |||
| } | |||
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These were moved to stats.ts for reuse.
pgarrison
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May 28, 2026
| }; | ||
| } finally { | ||
| await browser.close(); | ||
| await new Promise((res) => server.close(res)); |
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This was moved to line 182
pgarrison
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May 28, 2026
| // no HTTP range-request overhead, so DuckDB sort performance matches real-user timing. | ||
| const loaded = new Set(); | ||
| for (const source of testCases.flat()) { | ||
| if (source.label in loaded) continue; // Don't add duplicate sources |
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This whole section was moved verbatim to injectFixtures, with one exception: I changed this condition to loaded.has(source.label) to fix a bug. (in does not check set membership!)
pgarrison
requested review from
BrianWhitneyAI,
SeanDuHare and
aswallace
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BrianWhitneyAI
approved these changes
Jun 1, 2026
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Approved under the assumption the lint issues are cleaned up
SeanDuHare
approved these changes
Jun 2, 2026
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Waiting on https://github.com/AllenInstitute/biofile-finder/actions/runs/26973097008 to complete successfully after latest adjustments |
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Done 4576877 |
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Purpose
Enable benchmarking cold-start scenarios by using a new browser instance for every trial. This feature is enabled only when the user sets
warmups=0.Builds on #739, #806,
Changes
index.ts) accepts an optional list of tasks to run, and runs all tasks by default.run-benchmark-page.tsnow splits the logic intorunInBrowser(forwarmups > 0) andrunColdStartBenchmarks, which makes use ofrunInBrowser.ininstead ofhasfor set membership.stats.ts(may need a better name) andinjectFixturesfor DRY and readability.Testing
Without this change, running tests with
warmups=0shows a significant performance decrease for the first trial of each batch. The test below used 4 batches with 15 or 20 iterations each.Before:
After this change, with
warmups=0, there are no obvious outliers.After (2 batches, 5 iterations each):
