#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include <errno.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <signal.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "util.h"

#define WAITER_CPU 0
#define WAKER_CPU 1

pthread_mutex_t mutex;
pthread_cond_t cond;
pthread_barrier_t bar;
int flag;
pthread_t thr;
long t_cond_wait, t_fwq;
long nloop;
long blocktime = 10L * 1000 * 1000;

void *util_fn(void *arg)
{
	int i;
	int ret;
    long start, end;

	print_cpu_last_executed_on("Utility thread");

	ret = syscall(732);
	OKNGNOJUMP(ret == -1, "Utility thread is running on Linux\n");

	pthread_barrier_wait(&bar);
	for (i = 0; i < nloop; i++) {
		start = rdtsc_light();

		fwq(blocktime);

		end = rdtsc_light();
		t_fwq += end - start;

		pthread_mutex_lock(&mutex);
		flag = 1;
		pthread_cond_signal(&cond);
		pthread_mutex_unlock(&mutex);
		
	}

 fn_fail:
	return NULL;
}

static struct option options[] = {
	/* end */
	{ NULL, 0, NULL, 0, }
};

int main(int argc, char **argv)
{
	int i;
	int ret;
    long start, end;
	cpu_set_t cpuset;
	pthread_attr_t attr;
	pthread_barrierattr_t bar_attr;
	struct sched_param param = { .sched_priority = 99 };
	int opt;

	while ((opt = getopt_long(argc, argv, "+b:", options, NULL)) != -1) {
		switch (opt) {
			case 'b':
				blocktime = atoi(optarg);
				break;
			default: /* '?' */
				printf("unknown option %c\n", optopt);
				exit(1);
		}
	}
	nloop = (10 * 1000000000UL) / blocktime;
	printf("[INFO] nloop=%ld,blocktime=%ld\n", nloop, blocktime);

	
 	CPU_ZERO(&cpuset);
	CPU_SET(WAITER_CPU, &cpuset);
	if ((ret = sched_setaffinity(0, sizeof(cpu_set_t), &cpuset))) {
 		printf("Error: sched_setaffinity: %s\n", strerror(errno));
		goto fn_fail;
	}
	print_cpu_last_executed_on("Master thread");

	fwq_init();

	pthread_mutex_init(&mutex, NULL);
	pthread_cond_init(&cond, NULL);

	pthread_barrierattr_init(&bar_attr);
	pthread_barrier_init(&bar, &bar_attr, 2);

	ret = syscall(732);
	OKNGNOJUMP(ret != -1, "Master thread is running on McKernel\n");

	ret = syscall(731, 1, NULL);
	OKNGNOJUMP(ret != -1, "util_indicate_clone\n");

	if ((ret = pthread_attr_init(&attr))) {
 		printf("%s: Error: pthread_attr_init failed (%d)\n", __FUNCTION__, ret);
		goto fn_fail;
	}

 	CPU_ZERO(&cpuset);
	CPU_SET(WAKER_CPU, &cpuset);

	if ((ret = pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset))) {
 		printf("%s: Error: pthread_attr_setaffinity_np failed (%d)\n", __FUNCTION__, ret);
		goto fn_fail;
	}

	if ((ret = pthread_create(&thr, &attr, util_fn, NULL))) {
		fprintf(stderr, "Error: pthread_create failed (%d)\n", ret);
		goto fn_fail;
	}

	if ((ret = sched_setscheduler(0, SCHED_FIFO, &param))) {
		fprintf(stderr, "Error: sched_setscheduler failed (%d)\n", ret);
		goto fn_fail;
	}

	syscall(701, 1 | 2);
	pthread_barrier_wait(&bar);
	for (i = 0; i < nloop; i++) {
		start = rdtsc_light();
		
		pthread_mutex_lock(&mutex); /* no futex */
		while(!flag) {
			pthread_cond_wait(&cond, &mutex); /* 1st futex */
		}
		flag = 0;
		pthread_mutex_unlock(&mutex); /* 2nd futex */

		end = rdtsc_light();
		t_cond_wait += end - start;
	}
	syscall(701, 4 | 8);

	pthread_join(thr, NULL);
	printf("[INFO] waker: %ld cycles, waiter: %ld cycles, (waiter - waker) / nloop: %ld cycles\n", t_fwq, t_cond_wait, (t_cond_wait - t_fwq) / nloop);

	ret = 0;
 fn_fail:
	return ret;
}