test.cpp

#include <iostream>
#include <thread>
#include <ctime>

using namespace std;

void calc(unsigned long iterations) {
    unsigned long n = 0;
    for (unsigned long i = 0; i < iterations; i++) {
        n = n + n * (i % 5);
    }
}

clock_t test() {
    clock_t start = clock();
    thread *threads[8];

    for (int i = 0; i < 8; i++) {
        threads[i] = new thread(calc, 1024 * 1024 * 1024);
    }

    for (int i = 0; i < 8; i++) {
        (*threads[i]).join();
    }

    return clock() - start;
}

int main() {


    cout << "Time: " << ((double) test()) / CLOCKS_PER_SEC * 1000 << endl;
    return 0;
}

test.go

package main

import (
  "fmt"
  "syscall"
  "sync"
  )

func main() {
        var wg sync.WaitGroup

        var start syscall.Timeval
        syscall.Gettimeofday(&start)

        for i := 0; i < 8; i++ {
                wg.Add(1)
                go func(iterations int) {
                        defer wg.Done()
                        n := 0
                        for i := 0; i < iterations; i++ {
                            n = n + n * (i % 5)
                        }
                }(1024 * 1024 * 1024)
        }
        
        wg.Wait()
        var end syscall.Timeval
        syscall.Gettimeofday(&end)

        fmt.Printf("Time: %d \n", int((end.Usec-start.Usec) / 1000))
}