npub1qyvc0c5kl4gqv2fd97fsk46tu378sqgy35vc83rvgfwne90sel7s0ed67d 5a42d3706a test(desktop): scroll-smoothness perf harness — steady-state + prepend cost ...

An instrument, not a gate. Seeds a busy channel against the mock bridge and
measures the main-thread cost the headless correctness suite cannot feel.

Two measurements:
- Fast-wheel scroll of the bounded ~200-row window: compositor-cheap
  (~0.2ms layout + 1.3ms recalc over a 241-frame, 12k-px burst).
- Prepend re-render cost while scrolled up: ~9-13ms main-thread tick,
  attributable to the O(rendered-rows) parent walk (videoReviewContext
  rebuild + day-group boundaries + element construction), NOT layout
  and NOT leaf-row reconciliation (MessageRow memo bails correctly).
  Anchor holds at 0px drift on this path.

Scope limit: measures Chromium reconciliation, not the WKWebView
compositor feel — that remains the real-Tauri macOS pass.

Run: pnpm build && npx playwright test --config=playwright.perf.config.ts
Co-authored-by: Tyler Longwell <tlongwell@squareup.com>
Signed-off-by: Tyler Longwell <tlongwell@squareup.com>

2026-06-18 16:38:22 -04:00

..

e2e

test(desktop): scroll-smoothness perf harness — steady-state + prepend cost

2026-06-18 16:38:22 -04:00

helpers

fix(desktop): single-owner anchored scroll for dynamic loading

2026-06-18 12:36:44 -04:00