t.c

#include <unistd.h>
#include <linux/fcntl.h>

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <asm/unistd.h>
#include <signal.h>
#include <stdio.h>

static long
perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
                int cpu, int group_fd, unsigned long flags)
{
    int ret;

    ret = syscall(__NR_perf_event_open, hw_event, pid, cpu,
                   group_fd, flags);
    return ret;
}

static int counter = 0;

static void handler(int sig, siginfo_t *si, void *data)
{
  counter++;
}

int
main(int argc, char **argv)
{
    struct sigaction sa;

    sa.sa_sigaction = handler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_SIGINFO;
    sigaction(SIGRTMIN + 1, &sa, NULL);


    struct perf_event_attr pe;
    long long count;
    int fd;

    memset(&pe, 0, sizeof(struct perf_event_attr));
    pe.type = PERF_TYPE_SOFTWARE;
    pe.size = sizeof(struct perf_event_attr);
    pe.config = PERF_COUNT_SW_TASK_CLOCK;
    pe.sample_type = PERF_SAMPLE_IP;
    pe.disabled = 1;
    pe.exclude_kernel = 1;
    pe.exclude_hv = 1;
    pe.exclude_idle = 1;
    pe.wakeup_events = 10;

    fd = perf_event_open(&pe, 0, -1, -1, 0);
    if (fd == -1) {
       int e = errno;
       fprintf(stderr, "Error %d opening leader %llx\n", e, pe.config);
       exit(EXIT_FAILURE);
    }

//    fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK);
//    fcntl(fd, F_SETSIG, SIGRTMIN + 1);
//    fcntl(fd, F_SETOWN,getpid());

    if(fcntl(fd, F_SETOWN, getpid()) < 0)
         error(EXIT_FAILURE, errno, "failed to set dnotify signal");

    if(fcntl(fd, F_SETSIG, SIGRTMIN + 1) < 0)
         error(EXIT_FAILURE, errno, "failed to set dnotify signal");

//    if(fcntl(fd, F_NOTIFY, DN_MODIFY))
//     error(EXIT_FAILURE, errno,
//               "failed to register notification for '%s'", argv[1]);

    ioctl(fd, PERF_EVENT_IOC_RESET, 0);
    ioctl(fd, PERF_EVENT_IOC_ENABLE, 0);

    for (size_t i = 0; i < 10000; ++i)
    printf("Measuring instruction count for this printf\n");

    ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
    read(fd, &count, sizeof(long long));

    printf("Used %lld instructions\n", count);
    printf("Triggered %lld sigs\n", counter);

    close(fd);
}