RE: Memory woes

["Richard Ranft" <rranft@...>]

This might be useless, but why not simply start a new Lua VM when leaving
the menu to start the game, then dump the menu VM.  On game exit, start a
new Lua VM again for the menu and just drop the old "game" VM.  I can't see
how this would take any longer than dumping all scripts and then loading a
new set at each transition.  Unless memory allocation is so dreadfully slow
on the PS2 that it makes retaining the memory pool across states mandatory.

Just a thought, and probably not something you haven't already thought of.

Rich


> Subject: Memory woes
>
>
> We have a PS2 game that is in Beta and close to shipping now and
> I'm still
> having trouble tracking/controlling Lua's memory usage. Any tips would be
> greatly appreciated.
>
> Notes:
> 1. We use Lua 5.0.3 to script the entire game. Each script is an
> object that
> is loaded, run and collected individually as needed. We are loading a few
> hundred lua scripts for the non-game, once the player starts the game we
> unload all of these, and load a few hundred game scripts. Once game ends,
> reverse and repeat the process.
>
> 2. We do a memory dump from main menu, then run the game, then
> exit the game
> and do another dump from the main menu. Each time we do this
> cycle, memory
> associated with Lua has increased 145KB to 155KB. The things
> (quantity and
> exact items) being loaded both in game and out are fixed.
>
> 3. We do manual garbage collections after all unloads, prior to
> loads, and
> once again after the load has completed.
>
> 4. We have verified that the exact same objects are in memory at each
> snapshot.
>
> 5. We dumped the globals and registry tables and verified that the exact
> same keys are in lua at each snapshot.
>
> 6. The memory reported by lua as being in use doesn't change much
> (a few KB
> between runs).
>
> 7. Our internal memory manager traps all lua allocations and tags
> them so we
> know they are coming from lua. The increase in memory is memory
> used only.
> Fragmentation wouldn't effect the number.
>
> 8. Shutting down lua and restarting it isn't an option this late in the
> project.
>
> Debugging Lua isn't the easiest thing I have ever done. If anybody can
> suggest any additional checks or debugging strategies it would be greatly
> appreciated.
>
> Are there any code commentary docs anywhere that explain the internals of
> Lua?
>
> Thanks,
> Brett
>