Re: What's the difference between a "coroutine" and a "thread" in Lua?

[Asko Kauppi <askok@...>]

Does someone have a reason why VM based real multithreading would  
have better performance?

Lanes can do stack-to-stack copying of values at thread creation, and  
return value fetching, since the other thread is not running free at  
those cases. Therefore, I don't see that VM support would  
significantly change anything. Maybe on systems which do a lot of  
message passing, something can be done. Other than that, the whole of  
Lua will fit in modern CPU's cache, and all the OS threads will use  
the same code.

Jailing user-provided code and simplifying programming are surely  
benefits. Even when running on a single core CPU.  But also extension  
module based multithreading offers them conveniently.

-asko


Rob Kendrick kirjoitti 13.8.2007 kello 22:20:

> Asko Kauppi wrote:
> > To take this thread ;) in a helthier direction...
> >
> > Can you please list such tasks, where built-in pre-emptive
> > parallelism would have been useful.  My curiosity is as the author of
> > Lanes, wanting to know what couldn't be achieved by the current,
> > extension module based approach. "Certain tasks" was too vague.
>
> Well, I've certainly wished for similar when writing systems that need
> to run user-provided code at the same time as other user-provided  
> code.
>
> Also, while in most cases you could use co-routines, having a
> pre-emptive system simplifies the programmer's task, and having them
> implemented in the VM would yeild significantly better performance  
> than
> just using the OS's threads, I'd expect.
>
> B.