Disable GC entirely

[Dicebot]

On Wednesday, 10 April 2013 at 06:14:24 UTC, Rainer Schuetze 
wrote:
> I'm not sure if these have been proposed already in this long 
> thread, but 2 very small patches could help a lot for realtime 
> applications:
>
> 1. a thread local flag to disallow and detect GC allocations
> 2. a flag per thread to specify that the thread should not be 
> paused by the GC during collections.
>
> The latter would then put the responsibility on the programmer 
> to ensure that no references are mutated in the non-pausing 
> thread that don't exist anywhere else (to avoid the collection 
> of objects used in the realtime thread). As anything in a 
> realtime thread usually has to be pre-allocated anyway, that 
> doesn't put a lot more constraints on it but to ensure having 
> references to the pre-allocated data in other threads or global 
> state.

One concept is abused quite nicely in Erlang VM/GC - there is one 
gc instance per process(fiber) and it gets own pre-allocated 
memory pool for all its needs. That memory is prohibited to 
escape to other processes. When process lifespan is short enough 
(and it is Erlang Way, spawning hell lot of small processes), 
true garbage collection is never called, whole memory block is 
just sent back to pool on process termination.

I have tested it few times and such approach allowed to meet some 
soft real-time requirements. Don't know if something like that 
can be abused in D with its fibers and scope storage class.