From 1fe89b5daf054de511c23ac854b6186702b72cd3 Mon Sep 17 00:00:00 2001 From: Miguel Angel Simon Sierra Date: Sat, 1 Aug 2026 00:04:42 +0200 Subject: [PATCH] test(studio): record that the load instrumentation costs nothing measurable Interleaved A/B against the merge base on an identical 3,000-clip fixture: 4,679ms versus 4,733ms medians with fully overlapping ranges. A first pass ran the arms in blocks and reported +8.77%; that was arm ordering, not cost. Both results are recorded so the method is visible, not just the conclusion. --- packages/studio/tests/e2e/studio-load.baseline.json | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/packages/studio/tests/e2e/studio-load.baseline.json b/packages/studio/tests/e2e/studio-load.baseline.json index e41f28b653..3016fbe5b5 100644 --- a/packages/studio/tests/e2e/studio-load.baseline.json +++ b/packages/studio/tests/e2e/studio-load.baseline.json @@ -113,5 +113,18 @@ "measured": 1111170, "budget": 614400, "verdict": "FAIL \u2014 intended, U5 has not landed." + }, + "instrumentationOverhead": { + "question": "Does PR 1's instrumentation cost anything? It adds five marks, four measures, and one store subscription.", + "method": "Build-agnostic A/B: baseline c6925e471 and the PR branch served from separate worktrees on the same machine, identical 3,000-clip fixture. The baseline cannot emit hf.studio.* marks, so both arms were judged on a MutationObserver firing when the first [data-clip=\"true\"] node lands. 9 runs per arm, fresh browser each run, arms INTERLEAVED with alternating order per round.", + "baselineMedianMs": 4679, + "prMedianMs": 4733, + "deltaMs": 54, + "deltaPct": 1.15, + "baselineRangeMs": [4612, 5284], + "prRangeMs": [4600, 4918], + "rangesOverlap": true, + "verdict": "No measurable cost. The delta is 1.15% with fully overlapping ranges; the PR's range is narrower than the baseline's and its fastest run is faster. Instrumentation is free at this resolution.", + "methodNote": "A first attempt ran the arms in blocks rather than interleaved, with both dev servers alive, and reported +8.77%. That was an artifact of arm ordering and drift, not a real cost. Recorded here because the blocked result was wrong in a way that looked publishable." } }