wg-performance Quarterly Status Update 2019-09

[kristoferbaxter]

AMP Script

• WorkerDOM has been released 7 times this quarter so far.
• AMP Script was made generally available to all AMP documents.
• New Features: Local Storage / Session Storage, WebSockets, Global Event Subscriptions, Passing / Setting AMP State between threads.
• Performance Improvements for frequently used DOM Operations

AMP Service Worker

• Forced Nullification (forcing an existing ServiceWorker to be replaced with a nullified one) shipped.
• Work slowed due to slow adoption and staffing limitations.

AMP Performance Analysis Tool

• Tool complete and is usable by AMP Contributors to see the impact of their changes in synthetic environments.

AMP Performance

• Exiting micro-task loop (to macro-task) when a task exceeds a time threshold has shipped as a URL level opt-in, showing promising results on documents in production.
• Error Message Extraction (from strings to numerical identifiers) is near completion. This will provide a binary size reduction and a DX improvement since errors will link to amp.dev with additional context.
• Preload logic moved from HTMLLabelElements to Link Response Headers (2% faster install styles metric).
• Layers API Removed (2.5kb reduction)
• New Custom Elements v1 Polyfill removing older v0 Polyfill (4kb reduction)

[jridgewell]

• Launched <link ref=preload> extraction into Link Response Headers (2% faster Install Styles metric)
• Layers code removed (2.5kb)
• Custom elements v1 polyfill in Canary (will save 4kb once we remove v0 polyfill)

Edit: Moved into AMP Performance category.