[imtringued]

That doesn't solve the fundamental problem of stop the world pauses. If you had 10 threads sharing the same gc heap that allocate as much garbage as they want and 1 thread that has it's own heap that doesn't allocate anything only the 10 threads would be stopped by the garbage collector and you would have reached your goal.

If those 11 threads would share the same heap and 1 thread still doesn't use the gc because it's using manual memory management then you'd still suffer from stop the world pauses.

What you want is isolated heaps like erlang does, not manual memory management. I'm still wondering why we have no other programming languages with multiple heaps. You could probably achieve something similar with D and use of memory mapped files to efficiently share memory without copying bewteen processes. Alternatively you could call into C to spawn OS threads that don't suffer from stop the world pauses. But those two options are a hack. You're not supposed to use D like that.

I chose D as an example because it's a programming language with both a garbage collector and manual memory management that still suffers from stop the world pauses.