Re: [Vala] vala and actors model

[Fabien CELLIER <tallion users sourceforge net>]

Thanks a lot for your feedback. Thanks to your advice, I learn new things.


> A fully scalable actor model needs a work stealing thread pool
I don't understand, if you have a threadpool which share threads, why we
need work stealing? I know that if we want highly optimized code, we need
it, but the implementation is not trivial and need to recreate a lot of
code  (even for ABP worker) :). I think threadpool is enough for the
beginning, no?

> and for the task queues to live per-thread in that pool, and not per-actor.
you're right. I changed my code.. Now I push tasks.

In fact, with the new code, my tests have the following results: (execution
times for only one channel/mailbox)

0 actor (explicit call in the main thread) : 9.1337410689999992 seconds
1 actor (with his own thread) : 9.1125094860000004
10 actors : 4.6893007400000002
200000 actors : 4.7922086029999997 (with some issues for the malloc at the
beginning, I had to integrate a memory pool in C code ( (is it possible in
vala?) but I only look the execution, not initialization)
So, with 2 actors it's a little slower than the older code( 0.5 % :) but
it's seems to be ok.


PS: I'm bad with foreign language, so i hope i was clear :-°

Indeed an actor model for Vala would be a sweet deal. Perhaps an actor
> model could even replace a "mainloop concept" in the Dova profile
> (this is just me rambling :-)).
>
> Looking at your code I see two major issues that will prevent you from
> scaling into millions of actors:
>
>  * No work stealing
>  * The mailboxes are implemented as async queues living on a per-actor
> basis
>
> A fully scalable actor model needs a work stealing thread pool and for
> the task queues to live per-thread in that pool, and not per-actor.
> This way you will have extremely low lock contention.
>
> --
> Cheers,
> Mikkel