From 50b294c9201e8916e0474f2ca26733e6a99a5635 Mon Sep 17 00:00:00 2001 From: 4gray Date: Sun, 27 Sep 2026 10:01:10 +0200 Subject: [PATCH] docs(performance): note that Playwright pins pages visible Co-Authored-By: Claude Opus 5.5 --- docs/architecture/idle-work-audit-2026-09.md | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/docs/architecture/idle-work-audit-2026-09.md b/docs/architecture/idle-work-audit-2026-09.md index 5201b9920..f739177dc 100644 --- a/docs/architecture/idle-work-audit-2026-09.md +++ b/docs/architecture/idle-work-audit-2026-09.md @@ -89,6 +89,13 @@ The three worst offenders, in order: instruments. The instrumented pass had browser-process CPU of about 2.5 s per window and 550 wakeups/s, almost all of it the sampling profiler. +Playwright pins every page it attaches to as visible: `Emulation.setFocusEmulationEnabled` +raises the page's capturer count. The minimized windows above were measured +through Playwright. That is faithful for this build, because +`backgroundThrottling: false` keeps the page visible anyway. Measuring a build +where the window can become hidden needs a launch without Playwright over raw +CDP. The follow-up PRs do that. + Harness artifacts that were excluded: - The E2E fixture's own 60 Hz rAF frame counter (`startRendererFrameCapture`),