Re: Interrupting lua execution

["rodhydeuk" <rodhydeuk@...>]

I had a similar problem in that I had a bunch of lua contexts running 
in separate threads, synchronized with a master thread. Each lua 
context was only allowed to run for a short time before synchronizing 
with the master thread, partly because there was rendering 
involved, but mainly because I wanted to ensure that no one state 
could hog resources. The solution had 3 aspects.

a) use pthreads (ok, I'm mostly developing on Windows XP/2000, but I 
want portability and there are a few pthread libraries out there for 
Windows) and a synchronize function, called by every thread including 
in my case, the master thread.

b) use a count hook which is called every n instructions. I 
retrofitted one onto lua 4.01 but I think there's one as standard in 
5.0alpha. The hook callback calls the synchronize function.

c) ensure that some of the C/C++ functions called from Lua also 
invoke the synchronize function.

All my tests worked (once I got over the deadlocks). I'm not 
convinced that I needed threads to do this: in Windows I suspect that 
fibers would have done the trick.

--- Rod

--- In lua-l@y..., "Chris" <jlsfjs@y...> wrote:
> Hello,
> 
> after the VERY usefull help from Björn De Meyer I'm really 
considering lua
> as a first choice for my (small and parttime) game project...
> Six months ago I've done some tests with a skeleton application 
just to wrap
> and handle C++ <--> lua calls and that was fine.
> 
> But, now I'm facing another problem. My first idea was (as in this 
skeleton
> app) to attach a script context to every instance of a class that 
would need
> it.
> For example :
> CWorld (1 instance)
> CScene (few instances)
> CCharacter (several instances)
> CItems (many instances)
> CSectors (several)
> 
> Each C++ instance run its own lua context. This is very easy to do 
and very
> clean to code. But unfortunately I have now a main render loop that 
can't
> wait for a script to spend too long in its bytecode run. I can 
control which
> instance is eligible to call lua (or maybe next time if we allready 
spent
> too long in the instances loop)
> 
> How could I do to interrupt a vm and switch it back later to 
continue
> execution ? Is the debugger hook the one and only solution ? Is the 
overall
> idea ok ?
> 
> Thank you
> 
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