#include <stdio.h>
  #include <unistd.h>
  #include <stdlib.h>
  #include <stdbool.h>
  #include <string.h>
  #include <fcntl.h>
  #include <poll.h>
  #include <sys/ioctl.h>
  #include <linux/perf_event.h>
  #include <linux/bpf.h>
  #include "libbpf.h"
  #include "bpf_load.h"
  
  #define SAMPLE_PERIOD  0x7fffffffffffffffULL
  
  static void test_bpf_perf_event(void)
  {
  	int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
  	int *pmu_fd = malloc(nr_cpus * sizeof(int));

  	int status, i;

  
  	struct perf_event_attr attr_insn_pmu = {
  		.freq = 0,
  		.sample_period = SAMPLE_PERIOD,
  		.inherit = 0,
  		.type = PERF_TYPE_HARDWARE,
  		.read_format = 0,
  		.sample_type = 0,
  		.config = 0,/* PMU: cycles */
  	};
  
  	for (i = 0; i < nr_cpus; i++) {
  		pmu_fd[i] = perf_event_open(&attr_insn_pmu, -1/*pid*/, i/*cpu*/, -1/*group_fd*/, 0);

  		if (pmu_fd[i] < 0) {

  			printf("event syscall failed
  ");

  			goto exit;
  		}

  
  		bpf_update_elem(map_fd[0], &i, &pmu_fd[i], BPF_ANY);
  		ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0);
  	}

  	status = system("ls > /dev/null");
  	if (status)
  		goto exit;
  	status = system("sleep 2");
  	if (status)
  		goto exit;

  exit:

  	for (i = 0; i < nr_cpus; i++)
  		close(pmu_fd[i]);

  	close(map_fd[0]);

  	free(pmu_fd);
  }
  
  int main(int argc, char **argv)
  {
  	char filename[256];
  
  	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  
  	if (load_bpf_file(filename)) {
  		printf("%s", bpf_log_buf);
  		return 1;
  	}
  
  	test_bpf_perf_event();

  	read_trace_pipe();

  
  	return 0;
  }