Cpu cycles counter for linux in C++

 #include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <asm/unistd.h>

#include <linux/perf_event.h>

#include <sys/ioctl.h>

#include <fcntl.h>

#include <stdint.h>

// Structure for perf_event_attr

struct perf_event_attr pe;

// need permsiion  on perf_event_open

// to see value ->

// cat /proc/sys/kernel/perf_event_paranoid

//0: Allows access to all users to use perf_event_open for monitoring performance events.

//1: Allows access only to privileged users (typically root) to use perf_event_open.

//2: Disallows access to all users to use perf_event_open

//sudo sysctl kernel.perf_event_paranoid=<new_value>

// Function to initialize and read CPU cycle count

uint64_t read_cpu_cycles() {

    // Initialize perf_event_attr structure

    memset(&pe, 0, sizeof(struct perf_event_attr));

    pe.type = PERF_TYPE_HARDWARE;

    pe.config = PERF_COUNT_HW_CPU_CYCLES;

    // Open the event

    int fd = syscall(__NR_perf_event_open, &pe, 0, -1, -1, 0);

    if (fd == -1) {

        perror("Error opening leader %llx");

        //exit(EXIT_FAILURE);

        return 0;

    }

    // Read the counter

    uint64_t count;

    read(fd, &count, sizeof(uint64_t));

    // Close the event

    close(fd);

    return count;

}