concurrency-and-parallelism-in-js.md

"Concurrency & Parallelism in JS" by Naveed Ihsanullah

(video)

• Concurrency & parallelism
  • Concurrency is having multiple tasks run together (multitasking)
  • Parallelism is actually executing tasks separately (in hardware)
• Browser implementations of JS is fast and getting faster with asm.js etc
• Parallelism is bottlenecked by the hardware, and concurrency is bottlenecked by waiting on responses.
• Improving parallelism
  • Web workers
• Improving concurrency
  • Parallel JS -- still experimental etc
  • postMessage() -- performance isn't there
  • transfer buffers around
• Native has solved this. Do similar on the web: shared memory for JS
  • postMessage() + SharedArrayBuffer
  • use SharedInt32Array to view on it
  • the low-level details can be abstracted
• Availability
  • Landed in Firefox Nightly.
  • Announced for future Chrome too.
  • Unfortunately can't be polyfilled.