FWIW, I very much agree with Dave on this point. My conceptual model for microtask work is just a re-ordering of work which otherwise would have run synchronously, but wanted to be run with a fresh stack.
Microtask non-termination should not be different from "regular" script non-termination. On Mon, Aug 12, 2013 at 6:09 PM, David Herman <dher...@mozilla.com> wrote: > On Aug 12, 2013, at 5:43 PM, David Bruant <bruan...@gmail.com> wrote: > >>> - I see *no* reasonable alternative to runaway microtask churn other than >>> slow-script dialog. >> So did Dominic [1]. I suggested something else [2] and he found the idea >> interesting. What do you think? > > Quoting you from > >> [2] https://mail.mozilla.org/pipermail/es-discuss/2013-August/032630.html > > you said: > >> Maybe implementations could decide to break a microtask chain, but >> instead of prompting a dialog, they just break it and call a callback >> (later, in a different task, not microtask) so that the script knows and >> can try to recover. > > It is an interesting idea, I missed it the first time around; you might > describe it as an asynchronous TimeoutException. I'm thinking about it, but > I'm pretty skeptical. It's still effectively preemption semantics. At any > nondeterministic (and not portably defined) point, your code can simply be > stopped. It's not even clear what the atomicity guarantees would be around > valid preemption points in the semantics. For example, can you preempt code > halfway through the modification of a 64-bit word? Can you preempt code that > hasn't spilled its registers back to memory? Am I scaring you yet? ;-) > > Even if we could provide a fully well-specified definition for concurrent > interruption, I really have no idea how code could ever realistically recover > from such an event. The only thing the system tells you is "at some point in > some turn we just stopped you from whatever you were doing," and now you're > expected to reconstruct your state. This reminds me of exception safety in > C++. > > Dave > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
