Re: The Lua 5.1(work) GC

[Mark Hamburg <mhamburg@...>]

I can certainly sympathize with the view point that pre-emptive
multi-threading is more trouble than it's worth. On the other hand, on a
multi-processor machine, it would seem almost mandatory. If Lua is the glue
holding a system together, then presumably it also becomes the glue
coordinating the work being done by the processors. To do this would seem to
require a way to pass data structures across the processors -- i.e., across
threads -- and a shared Lua universe seems the simplest way to do so. (I say
Lua universe to distinguish from lua_State which actually is synonymous with
a Lua thread.) Do you have recommendations for some other scheme? How should
messaging between Lua processes work?

Mark

on 5/25/04 12:31 PM, Roberto Ierusalimschy at roberto@inf.puc-rio.br wrote:

>> I'm just getting ready to look at 5.1 (after I clean up some uses
>> of .n).  One thing I'm curious about is whether it does anything to
>> reduce the need to lock the Lua state when manipulating the stack.
> 
> No. We do not think that "real multithreading" in Lua (that is, several
> preemptive threads sharing a single Lua state) is really a good idea and
> so it is not high in our list of priorities. There are several options,
> such as coroutines (i.e., non-preemptive multithreading) or threads with
> independent Lua states ("Lua processes"). (One thing we are trying to
> improve is the ability to yield inside metamethods and for iterators.)
> 
> -- Roberto