/*
 * Tasks (read, write, load)
 * by matsu@igel.co.jp
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>

#define MAXNAMELEN 32
#define MAXTHREADS 32
#define PROC_CURRENTIME "/proc/currentime"
#define PROC_UPTIME "/proc/uptime"
#define N_REP 10000
#define SIGNAL_INTERVAL 16 /* ms */

struct irqfile {
    unsigned long irq;
    char name[MAXNAMELEN];
};

struct timeval tv0[N_REP], tv1[N_REP], tv2[N_REP], tv_s, tv_e;

static void irqhandle(void *arg) {
    struct irqfile *irqf = (struct irqfile *)arg;
    int fd;
    volatile int i;
    static float waste;

    if ((fd = open(irqf->name, O_RDONLY)) < 0) {
	perror("open proc file");
	pthread_exit(NULL);
    }

    fprintf(stderr, "irqhandle: waiting for irq...\n");

    for(i=0; i<N_REP; i++) {
	/* wait for irq */
	if (read(fd, &tv1[i], sizeof(struct timeval)) !=
	    sizeof(struct timeval)) {
	    perror("read proc file");
	    pthread_exit(NULL);
	}
	gettimeofday(&tv2[i], NULL);
    }
    gettimeofday(&tv_e, NULL);

    pthread_exit(NULL);
}

static void irqgen(void *arg) {
    struct irqfile *irqf = (struct irqfile *)arg;
    int fd;
    unsigned char ch  = 'a';
    volatile int i;
    struct timespec ts;
    static float waste;
    static char buf[BUFSIZ];
    
    if ((fd = open(irqf->name, O_WRONLY)) < 0) {
	perror("open proc file");
	pthread_exit(NULL);
    }
    
    fprintf(stderr, "irqgen: waiting for seconds...\n");
    sleep(5);
    fprintf(stderr, "irqgen: go!\n");
    
    /* send irq signal*/
    gettimeofday(&tv_s, NULL);
    for (i=0; i<N_REP; i++) {
    
	gettimeofday(&tv0[i], NULL);
	if (write(fd, &ch, sizeof(char)) < 0) {
	    perror("write proc file");
	    pthread_exit(NULL);
	}
	
	ts.tv_sec = 0;
	ts.tv_nsec = SIGNAL_INTERVAL * 1000 * 1000;
	nanosleep(&ts, NULL);
    }
    
    pthread_exit(0);
}

static void cpuhamper(void) {
    struct timespec ts;

    ts.tv_sec = 0;
    ts.tv_nsec = 1000;

    while (1) {
	nanosleep(&ts, NULL);
    }
    pthread_exit(0);
}

static void iohamper(void) {
    struct timespec ts;
    int fd;
    char ch = 'a';
    

    ts.tv_sec = 0;
    ts.tv_nsec = 0;

    if ((fd = open("/tmp/a", O_RDWR | O_CREAT | O_TRUNC, 0666)) < 0) {
	perror("open /tmp/a");
	pthread_exit(0);
    }

    while (1) {
	write(fd, &ch, sizeof(char));
	nanosleep(&ts, NULL);
    }
}

int main(int argc, char *argv[]) {
    pthread_t th[MAXTHREADS];
    pthread_attr_t thattr;
    struct irqfile *irqf;
    unsigned long dt0, dt1, offset;
    struct sched_param sp;
    int i, j, hams;
    static struct timeval start, end;
    static struct timespec ts;

    offset = 0;
    for (i=0; i<100; i++) {
	gettimeofday(&start, NULL);
    	gettimeofday(&end, NULL);
    	offset += ((end.tv_sec)*1000*1000+(end.tv_usec)) -
		((start.tv_sec)*1000*1000+(start.tv_usec));
    }
    offset /= 100;
    fprintf(stderr, "offset = %ld\n", offset);
    
    if ((argc < 3) || (argc > 4)) {
	fprintf(stderr, "Usage: %s irq_no num_of_hamper "
	       "[priority_for_irqhandler]\n", argv[0]);
	return -1;
    }

    irqf = (struct irqfile *)malloc(sizeof(struct irqfile));
    if (!irqf) return -1;
    irqf->irq = strtoul(argv[1], NULL, 0);
    memset(irqf->name, 0, MAXNAMELEN);
    sprintf(irqf->name, "/proc/irqhook/%d", irqf->irq);

    pthread_attr_init(&thattr);
    
    /* user-level irq handler thread */
    pthread_create(&th[0], NULL, (void (*))irqhandle, (void *)irqf);
    if ((argc == 4) &&
	((sp.sched_priority = strtoul(argv[3], NULL, 0)) > 0)) {
	if (!pthread_setschedparam(th[0], SCHED_RR, &sp));
    }

    /* hamper threads */
    ts.tv_sec = 0; ts.tv_nsec = 3000;
    hams = strtoul(argv[2], NULL, 0);
    for (i=2; i<(hams + 2); i++) {
	nanosleep(&ts, NULL);
    	pthread_create(&th[i], NULL, (void (*))cpuhamper, NULL);
    }
	
    /* virtual irq generator thread */
    pthread_create(&th[1], NULL, (void (*))irqgen, (void *)irqf);
    if ((argc == 4) &&
	((sp.sched_priority = strtoul(argv[3], NULL, 0) + 1) > 0)) {
	if (!pthread_setschedparam(th[1], SCHED_RR, &sp));
    }

    pthread_join(th[0], NULL);
    pthread_join(th[1], NULL);

    for (i=0; i<N_REP; i++) {
#if 0	
	dt0 = (tv2[i].tv_sec)*1000*1000+(tv2[i].tv_usec) -
	    ((tv1[i].tv_sec)*1000*1000+(tv1[i].tv_usec)) - offset;
	dt1 = (tv2[i].tv_sec)*1000*1000+(tv2[i].tv_usec) -
	    ((tv0[i].tv_sec)*1000*1000+(tv0[i].tv_usec)) - offset;
#else
	dt0 = (tv2[i].tv_sec - tv1[i].tv_sec)*1000*1000 -
	    tv1[i].tv_usec - offset + tv2[i].tv_usec;
	dt1 = (tv2[i].tv_sec - tv0[i].tv_sec)*1000*1000 -
	    tv0[i].tv_usec - offset + tv2[i].tv_usec;
#endif	
    
	printf("%02d,%ld,%ld\n", i, dt0, dt1);
    }
    fprintf(stderr, "total = %ld - %ld = %ld, %ld\n",
	    (tv_e.tv_sec)*1000*1000+(tv_e.tv_usec),
	    (tv_s.tv_sec)*1000*1000+(tv_s.tv_usec),
	    ((tv_e.tv_sec)*1000*1000+(tv_e.tv_usec)) -
	    ((tv_s.tv_sec)*1000*1000+(tv_s.tv_usec)) -
	    offset * (N_REP + 1),
	    (((tv_e.tv_sec)*1000*1000+(tv_e.tv_usec)) -
	    ((tv_s.tv_sec)*1000*1000+(tv_s.tv_usec)) - 
	     offset * (N_REP + 1)) / N_REP);
}