Re: Scalability of Lua, many small vs. few big lua_States?

[Andrew Starks <andrew.starks@...>]

On Monday, January 27, 2014, Dirk Laurie <dirk.laurie@gmail.com> wrote:
> 2014-01-27 Dirk Zoller <duz@sol-3.de>:
>
> > Think of a spreadsheet where in some cells the user can run a script to
> > process data. A lua_State is created per line. People build larger setups
> > than the developer anticipated. Typically, each script terminates within
> > micros. Yet there are many and they are called frequently.
> >
> > It runs on a 16 cpu server. It runs well, load is nicely balanced. Problems
> > are spurious lockups or crashes. I want to simplify it. It has grown to
> > complex.
> >
> > Now if I redesign it to use fewer lua_States that would be nicer. But I'd
> > rather not then see performance hickups come in and learn that the original
> > design was actually better.
>
> A lua_State is simply a thread, and if you are only accessing it via
> the coroutine
> library it is idiomatic Lua (=nice) even if you have a huge table of coroutines.
>
> If it ain't broke, don't fix it.

Sounds like it is at least breaking. :)

I've found that a socket interface works really well with coroutines and that a mix of the two is an almost transparent interface to "services" (not so much objects) that are in the existing lua_state, another thread or across a socket. 

But so far, this is a wip for me. I fear that any detail would contain bad advice. 

-Andrew