Re: Garbage Collection bottleneck

[Joshua Jensen <jjensen@...>]

Brian Weed wrote:
> We are using Lua 5.02 in our game engine, and although we had no 
> problems on previous projects, the garbage collection now seems to be 
> a bottleneck (noticable pause in the main loop when the GC executes).
>
> The problem stems from my creation of some temporary global variables 
> inside each tick of the main loop.
>
> Although it seems that the incremental GC of Lua v5.1 would probably 
> solve this problem, upgrading is a last resort...I am looking for 
> solutions that don't involve upgrading.
You could look into luarc, a reference counted version of Lua.  It 
doesn't have the 5.0.3 fixes in it, but I do believe it is current to 
5.0.2 (although a failing memory never helps).  Its webpage is at 
http://luaplus.org/tiki-index.php?page=luarc.  You want the build out of 
Subversion.

The reference counting seems stable and there is really no performance 
comparison between the standard mark-sweep collector (which still exists 
in luarc to handle table cycles) and the reference counting's ability to 
destroy objects immediately.  The reference counting Lua has shipped a 
number of Xbox and Xbox 360 console titles, although they've only 
shipped through LuaPlus (which is where the reference counting was 
born).  I believe all LuaPlus reference counting changes are merged into 
luarc.

Josh