Processes and Channels, cf. goroutines.

[Sean Kelly]

Okay, just for fun, here are some results with the new scheduler.
   I injected periodic yields into the code to simulate the
yielding that would happen automatically if the code was using
send and receive.  First the code:


shared long count = 0;

shared static ~this() {
	writefln("count = %s", count);
}

void childThread() {
	foreach(i; 0 .. 1_000) {
		atomicOp!"+="(count, 1);
		if (scheduler && 0 == i % 100)
			scheduler.yield();
	}
}

void mainThread() {
	foreach(i; 0 .. 100_000) {
		auto tid = spawn(&childThread);
	}
}

void runFibers() {
	scheduler = new FiberScheduler;

	scheduler.start(() {
		mainThread();
	});
}

void main(string[] args) {
	if (args.length > 1 && args[1] == "threads")
		mainThread();
	else if (args.length > 1 && args[1] == "fibers")
		runFibers();
	else writeln("specify threads or fibers");
}


And the results:


$ time concurrency threads
count = 100000000

real	1m11.033s
user	1m23.944s
sys	0m29.272s

$ time concurrency fibers
count = 100000000

real	0m5.998s
user	0m3.536s
sys	0m2.455s


I've got to say that I was surprised how fast 1 million kernel
threads were for this task.  That's orders of magnitude beyond
what I'd consider a sane number.