/*
 * rt-migrate-test.c
 *
 * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License (not later!)
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <stdarg.h>
#include <unistd.h>
#include <time.h>
#include <sys/time.h>
#include <unistd.h>
#define __USE_GNU
#define __USE_UNIX98
#include <sched.h>
#include <pthread.h>

#define VERSION_STRING "V 0.2"

int nr_tasks;

#define nano2sec(nan) (nan / 1000000000ULL)
#define nano2ms(nan) (nan / 1000000ULL)
#define nano2usec(nan) (nan / 1000ULL)
#define usec2nano(sec) (sec * 1000ULL)
#define ms2nano(ms) (ms * 1000000ULL)
#define sec2nano(sec) (sec * 1000000000ULL)
#define INTERVAL ms2nano(100ULL)
#define RUN_INTERVAL ms2nano(20ULL)
#define NR_RUNS 50
#define PRIO_START 2
#define MAX_ERR  usec2nano(100ULL)

#define PROGRESS_CHARS 70

static unsigned long long interval = INTERVAL;
static unsigned long long run_interval = RUN_INTERVAL;
static int nr_runs = NR_RUNS;
static int prio_start = PRIO_START;
static int check;

static unsigned long long now;

static int done;
static int loop;

static pthread_barrier_t start_barrier;
static pthread_barrier_t end_barrier;
static unsigned long long **intervals;
static unsigned long long **intervals_length;
static unsigned long **intervals_loops;

static char buffer[BUFSIZ];

static void perr(char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buffer, BUFSIZ, fmt, ap);
	va_end(ap);

	perror(buffer);
	fflush(stderr);
	exit(-1);
}

static void err(char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buffer, BUFSIZ, fmt, ap);
	va_end(ap);

	fprintf(stderr, buffer);
	fflush(stderr);
	exit(-1);
}

static void print_progress_bar(int percent)
{
	int i;
	int p;

	if (percent > 100)
		percent = 100;

	/* Use stderr, so we don't capture it */
	putc('\r', stderr);
	putc('|', stderr);
	for (i=0; i < PROGRESS_CHARS; i++)
		putc(' ', stderr);
	putc('|', stderr);
	putc('\r', stderr);
	putc('|', stderr);

	p = PROGRESS_CHARS * percent / 100;

	for (i=0; i < p; i++)
		putc('-', stderr);

	fflush(stderr);
}

static void usage(char **argv)
{
	char *arg = argv[0];
	char *p = arg+strlen(arg);

	while (p >= arg && *p != '/')
		p--;
	p++;

	printf("%s %s\n", p, VERSION_STRING);
	printf("Usage:\n"
	       "%s <options> nr_tasks\n\n"
	       "-p prio --prio  prio        base priority to start RT tasks with (2) \n"
	       "-r time --run-time time     Run time (ms) to busy loop the threads (20)\n"
	       "-s time --sleep-time time   Sleep time (ms) between intervals (100)\n"
	       "-l loops --loops loops      Number of iterations to run (50)\n"
	       "-c    --check               Stop if lower prio task is quick than higher (off)\n"
	       "  () above are defaults \n",
		p);
	exit(0);
}

static void parse_options (int argc, char *argv[])
{
	for (;;) {
		int option_index = 0;
		/** Options for getopt */
		static struct option long_options[] = {
			{"prio", required_argument, NULL, 'p'},
			{"run-time", required_argument, NULL, 'r'},
			{"sleep-time", required_argument, NULL, 's'},
			{"loops", required_argument, NULL, 'l'},
			{"loops", no_argument, NULL, 'c'},
			{"help", no_argument, NULL, '?'},
			{NULL, 0, NULL, 0}
		};
		int c = getopt_long (argc, argv, "p:r:s:l:h",
			long_options, &option_index);
		if (c == -1)
			break;
		switch (c) {
		case 'p': prio_start = atoi(optarg); break;
		case 'r': run_interval = atoi(optarg); break;
		case 's': interval = atoi(optarg); break;
		case 'l': nr_runs = atoi(optarg); break;
		case 'c': check = 1; break;
		case '?':
		case 'h':
			usage(argv);
			break;
		}
	}

}

static unsigned long long get_time(void)
{
	struct timeval tv;
	unsigned long long time;

	gettimeofday(&tv, NULL);

	time = sec2nano(tv.tv_sec);
	time += usec2nano(tv.tv_usec);

	return time;
}

static void record_time(int id, unsigned long long time, unsigned long l)
{
	unsigned long long ltime;

	if (loop >= nr_runs)
		return;
	time -= now;
	ltime = get_time();
	ltime -= now;
	intervals[loop][id] = time;
	intervals_length[loop][id] = ltime;
	intervals_loops[loop][id] = l;
}

static void print_results(void)
{
	int i;
	int t;
	unsigned long long tasks_max[nr_tasks];
	unsigned long long tasks_min[nr_tasks];
	unsigned long long tasks_avg[nr_tasks];

	memset(tasks_max, 0, sizeof(tasks_max[0])*nr_tasks);
	memset(tasks_min, 0xff, sizeof(tasks_min[0])*nr_tasks);
	memset(tasks_avg, 0, sizeof(tasks_avg[0])*nr_tasks);

	printf("Iter: ");
	for (t=0; t < nr_tasks; t++)
		printf("%6d  ", t);
	printf("\n");

	for (i=0; i < nr_runs; i++) {
		printf("%4d:   ", i);
		for (t=0; t < nr_tasks; t++) {
			unsigned long long itv = intervals[i][t];

			if (tasks_max[t] < itv)
				tasks_max[t] = itv;
			if (tasks_min[t] > itv)
				tasks_min[t] = itv;
			tasks_avg[t] += itv;
			printf("%6lld  ", nano2usec(itv));
		}
		printf("\n");
		printf(" len:   ");
		for (t=0; t < nr_tasks; t++) {
			unsigned long long len = intervals_length[i][t];

			printf("%6lld  ", nano2usec(len));
		}
		printf("\n");
		printf(" loops: ");
		for (t=0; t < nr_tasks; t++) {
			unsigned long loops = intervals_loops[i][t];

			printf("%6ld  ", loops);
		}
		printf("\n");
		printf("\n");
	}

	for (t=0; t < nr_tasks; t++) {
		printf(" Task %d (prio %d):\n", t, t + prio_start);
		printf("   Max: %lld us\n", nano2usec(tasks_max[t]));
		printf("   Min: %lld us\n", nano2usec(tasks_min[t]));
		printf("   Tot: %lld us\n", nano2usec(tasks_avg[t]));
		printf("   Avg: %lld us\n", nano2usec(tasks_avg[t] / nr_runs));
		printf("\n");
	}
}

static unsigned long busy_loop(unsigned long long start_time)
{
	unsigned long long time;
	unsigned long l = 0;

	do {
		l++;
		time = get_time();
	} while ((time - start_time) < RUN_INTERVAL);

	return l;
}

void *start_task(void *data)
{
	long id = (long)data;
	unsigned long long start_time;
	struct sched_param param = {
		.sched_priority = id + prio_start,
	};
	int ret;
	int high = 0;
	cpu_set_t cpumask;
	cpu_set_t save_cpumask;
	int cpu = 0;
	unsigned long l;

	ret = sched_getaffinity(0, sizeof(save_cpumask), &save_cpumask);
	if (ret < 0)
		perr("getting affinity");

	/* Check if we are the highest prio task */
	if (id == nr_tasks-1)
		high = 1;

	ret = sched_setscheduler(0, SCHED_FIFO, &param);
	if (ret < 0 && !id)
		fprintf(stderr, "Warning, can't set priorities\n");

	while (!done) {
		if (high) {
			/* rotate around the CPUS */
			if (!CPU_ISSET(cpu, &save_cpumask))
				cpu = 0;
			CPU_ZERO(&cpumask);
			CPU_SET(cpu, &cpumask); cpu++;
			sched_setaffinity(0, sizeof(cpumask), &cpumask);
		}
		pthread_barrier_wait(&start_barrier);
		start_time = get_time();
		l = busy_loop(start_time);
		record_time(id, start_time, l);
		pthread_barrier_wait(&end_barrier);
	}

	return NULL;
}

static int check_times(int l)
{
	int i;
	unsigned long long last;

	for (i=0; i < nr_tasks; i++) {
		if (i && last < intervals[l][i] &&
		    ((intervals[l][i] - last) > MAX_ERR)) {
			printf("last %lld int %lld i %d loop %d\n",
			       last, intervals[l][i], i, l);
			return 1; }
		last = intervals[l][i];
	}
	return 0;
}

int main (int argc, char **argv)
{
	pthread_t *threads;
	long i;
	int ret;
	struct timespec intv;
	struct sched_param param;

	parse_options(argc, argv);

	if (argc < (optind + 1))
		usage(argv);

	nr_tasks = atoi(argv[optind]);
	threads = malloc(sizeof(*threads) * nr_tasks);
	if (!threads)
		perr("malloc");
	memset(threads, 0, sizeof(*threads) * nr_tasks);

	ret = pthread_barrier_init(&start_barrier, NULL, nr_tasks + 1);
	ret = pthread_barrier_init(&end_barrier, NULL, nr_tasks + 1);
	if (ret < 0)
		perr("pthread_barrier_init");

	intervals = malloc(sizeof(void*) * nr_runs);
	if (!intervals)
		perr("malloc intervals array");

	intervals_length = malloc(sizeof(void*) * nr_runs);
	if (!intervals_length)
		perr("malloc intervals length array");

	intervals_loops = malloc(sizeof(void*) * nr_runs);
	if (!intervals_loops)
		perr("malloc intervals loops array");

	for (i=0; i < nr_runs; i++) {
		intervals[i] = malloc(sizeof(unsigned long long)*nr_tasks);
		if (!intervals[i])
			perr("malloc intervals");
		memset(intervals[i], 0, sizeof(unsigned long long)*nr_tasks);

		intervals_length[i] = malloc(sizeof(unsigned long long)*nr_tasks);
		if (!intervals_length[i])
			perr("malloc length intervals");
		memset(intervals_length[i], 0, sizeof(unsigned long long)*nr_tasks);

		intervals_loops[i] = malloc(sizeof(unsigned long)*nr_tasks);
		if (!intervals_loops[i])
			perr("malloc loops intervals");
		memset(intervals_loops[i], 0, sizeof(unsigned long)*nr_tasks);
	}

	for (i=0; i < nr_tasks; i++) {
		if (pthread_create(&threads[i], NULL, start_task, (void *)i))
			perr("pthread_create");

	}

	/*
	 * Progress bar uses stderr to let users see it when
	 * redirecting output. So we convert stderr to use line
	 * buffering so the progress bar doesn't flicker.
	 */
	setlinebuf(stderr);

	/* up our prio above all tasks */
	memset(&param, 0, sizeof(param));
	param.sched_priority = nr_tasks + prio_start;
	sched_setscheduler(0, SCHED_FIFO, &param);

	intv.tv_sec = nano2sec(INTERVAL);
	intv.tv_nsec = INTERVAL % sec2nano(1);

	print_progress_bar(0);

	for (loop=0; loop < nr_runs; loop++) {
		now = get_time();

		pthread_barrier_wait(&start_barrier);

		nanosleep(&intv, NULL);

		print_progress_bar((loop * 100)/ nr_runs);

		pthread_barrier_wait(&end_barrier);

		if (check && check_times(loop)) {
			loop++;
			nr_runs = loop;
			break;
		}
	}

	putc('\n', stderr);

	pthread_barrier_wait(&start_barrier);
	done = 1;
	pthread_barrier_wait(&end_barrier);

	for (i=0; i < nr_tasks; i++)
		pthread_join(threads[i], NULL);

	print_results();

	return 0;
}