bitvid/daily-perf-report-2026-02-13.md

Daily Perf Report - 2026-02-13

Summary

Implemented visibility gating for VideoEventBuffer to prevent UI thrashing when the tab is hidden. Audited upload documentation against implementation.

P0/P1 Findings

• P1 - VideoEventBuffer Thrashing: The VideoEventBuffer was flushing events and triggering UI callbacks every 75ms regardless of visibility. This wasted CPU on layout/paint recalculations for hidden tabs.
  • Fix: Modified flush() to buffer updates when document.hidden is true, and flush them in a batch upon visibilitychange.
• P2 - Upload Limits: Documentation states a 2GB limit due to client-side hashing. Verification confirmed js/utils/torrentHash.js reads the file for hashing, which is memory-bound in browsers. Docs are accurate.

Metrics

• Login Time: (Not measured this run)
• Queue Sizes: (Not measured this run)

PRs / Changes

• VideoEventBuffer: Added visibility gating.

Blockers & Decisions

• Decision: Prioritized VideoEventBuffer fix over WatchHistory backoff as it affects the main feed loop directly.
• Decision: Accepted the 2GB upload limit documentation as accurate for the current architecture.

Next Steps

• Investigate WatchHistory republish loop for similar visibility gating.
• Consider using streaming hashing (e.g., crypto.subtle) to lift the 2GB limit in the future.