#include <u.h>
#include <libc.h>
#include <thread.h>

Channel 		*cchan, *pchan;
ulong		iterations	= 0;
ulong		misses	= 0;
enum { Parent, Child, };
int 			state		= Parent;

void
child(void *unused)
{
	char data = '1';

	USED(unused);
	for (;;) {
		recv(cchan, &data);
		if (state == Parent) {
			++iterations;
			state = Child;
		}
		else {
			++misses;
		}
		send(pchan, &data);
	}
}

void
threadmain(int argc, char **argv)
{
	vlong 	tbegin, tend;
	double 	diff;
	char 		data = '1';

	USED(argc, argv);

	cchan = chancreate(sizeof(char), 1);
	pchan = chancreate(sizeof(char), 1);

	threadcreate(child, nil, 1024);	/* could be even smaller? */

	tbegin = nsec();
	while (iterations < 1000000) {
		send(cchan, &data);
		recv(pchan, &data);
		if (state == Child) {
			++iterations;
			state = Parent;
		}
		else {
			++misses;
		}
	}
	tend = nsec();

	diff = (tend - tbegin)/1000000000.0;

	print("did %ld iterations in %f seconds\n",iterations,diff);
	print("%.0f iterations/second\n",(float)iterations/diff);
	print("%ld misses\n",misses);

	threadexitsall(nil);
}