Re: Garbage Collection bottleneck

["Brian Weed" <brianweed@...>]

On 6/21/06, Joshua Jensen <jjensen@workspacewhiz.com> wrote:

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

Turns out I was using Lua 5.0 and not 5.0.2...

Using luarc does fix my problem in a small sample test app, but unfortunately it also crashes in my production code.  Before I try to track down that problem, I will try upgrading to Lua 
v5.1.x

Thanks.

Brian