[dherman]

By way of update from the standards trenches: threads are indeed a part of the WebAssembly plan, and we're also actively working on standardizing the SharedArrayBuffer API for JavaScript, which would allow an asm.js implementation with threads (either as a direct compilation target or as a WebAssembly polyfill). Shu-yu Guo has been working on drafting the SharedArrayBuffer spec and is planning to present an update in the next standards meeting in a couple weeks.

[syg]

Shu here. I'm the person drafting the memory model for the SharedArrayBuffer spec, and as Dave says, it'll be the basis for the wasm story as well.

Lars Hansen deserves most of the credit for the actual spec -- I'm just doing the memory model. :)

[johnbender]

Shu,

The concurrency/memory model nerds out here would love to see an early draft if at all possible :)

If nothing else, is it going to be weaker than sequential consistency?

[syg]

The current draft is available at http://tc39.github.io/ecmascript_sharedmem/shmem.html

The two strengths provided by the model are sequentially consistent atomics and something between the strengths of C++'s non-atomics and relaxed atomics. Races are fully defined, and there is no undefined behavior or undefined values.

I'm happy to discuss things more in a new thread or in private communication and would prefer to not derail this thread about VLC.

[johnbender]

Thank you!