No More Callbacks: 10,000 Actors, 10,000 Threads, 10,000 Spaceships

Re:No More Callbacks: 10,000 Actors, 10,000 Threads, 10,000 ... by pron on Wednesday October 16, 2013 @12:43PM (#6560652)

I agree. That's why Quasar starts by providing true lightweight threads - you can block, wait on conditions - whatever. Only, you can have millions of those.

On top of these fibers, Quasar gives you Go-like channels and/or Erlang-like actors (I say Erlang like because they follow the Erlang model closely: you pull messages rather than implement message callbacks, they have selective receive etc.)

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Re:No More Callbacks: 10,000 Actors, 10,000 Threads, 10,000 ... by rdtsc on Wednesday October 16, 2013 @01:18PM (#6560844)

Quasar looks very cool. How does pre-emption work? I know Erlang's VM count an actors' "reductions" -- bytecode instruction and after a certain number preempts that actor and lets other run. How does that work in Quasar? Does an actor have to explicitly yield, sleep, do IO or run receive?

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Re:No More Callbacks: 10,000 Actors, 10,000 Threads, 10,000 ... by pron on Wednesday October 16, 2013 @01:32PM (#6560944)

We've experimented with reduction-based preemption but saw no perceivable performance benefit (you can look at the Fiber class code and see them commented out). We might bring it back if we find a good use for it.

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Re:No More Callbacks: 10,000 Actors, 10,000 Threads, 10,000 ... by lmm on Thursday October 17, 2013 @08:32AM (#6564903)

Does that mean this system is inappropriate for CPU-bound tasks?

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Re:No More Callbacks: 10,000 Actors, 10,000 Threads, 10,000 ... by pron on Thursday October 17, 2013 @08:37AM (#6564925)

The spaceships demo is very much CPU bound.

But, at least for the time being I wouldn't run a long-running, CPU heavy computation in a fiber, but in a plain thread. Fibers work best when they block often.

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