Re: core.thread.Fiber --- runtime stack overflow unlike goroutines

[Dicebot via Digitalmars-d-learn]

On Friday, 15 August 2014 at 15:50:30 UTC, Dicebot wrote:
On Friday, 15 August 2014 at 15:40:35 UTC, Sean Kelly wrote:
On Friday, 15 August 2014 at 15:25:23 UTC, Dicebot wrote:

No, I was referring to the proposal to supply bigger stack 
size to Fiber constructor - AFAIR it currently does allocate 
that memory eagerly (and does not use any OS CoW tools), 
doesn't it?

I thought it did, but apparently the behavior of VirtualAlloc 
and mmap (which Fiber uses to allocate the stack) simply 
reserves the range and then commits it lazily, even though 
what you've told it to do is allocate the memory.  This is 
really great news since it means that no code changes will be 
required to do the thing I wanted to do anyway.

Guess that means some experimenting this weekend for me too :)

Looks like it indeed just magically works. I have used this 
simple program:

import core.thread;

void foo()
{
//  int[10240] array;
    Fiber.yield();
    for (;;) {}
}

void main()
{
    foreach (_ ; 0 .. 10_000)
    {
        //auto fiber = new Fiber(&foo);
        auto fiber = new Fiber(&foo, 100_000);
        fiber.call();
    }
}

And checked peak memory profile via `time --format="%M"`. Fiber 
constructor argument size did not change memory consumption at 
all, only changing size of fiber stack variables did.