Here is "False sharing" example, you can try it in VS with enabled OpenMP flag. Also if you enable speed optimization for compiler single thread version will be faster, but you can see false sharing effect too.

#include <iostream>
#include <ctime>
#include <omp.h>

using std::cout;
using std::endl;

const double M=8e8;

//single thread work to do
void one_thread() 
{
    long int n1=1, n2=1;
    for(; n1<M; n1+=n1%3);
    for(; n2<M; n2+=n2%3);
    cout << "Sum = " << n1 + n2 << endl;
}


//multi thread work to do
void multi_thread() 
{
    struct T
    {
        long int n1;
        char chuck[64];//should be commented to see false sharing effect
        long int n2;
    } t;
    t.n1 = 1;
    t.n2 = 1;
    #pragma omp parallel num_threads(2) shared(M,t)
    {
        #pragma omp sections
        {
            #pragma omp section
            for(; t.n1<M; t.n1+=t.n1%3);

            #pragma omp section
            for(; t.n2<M; t.n2+=t.n2%3);
        }
    }
    cout << "Sum = " << t.n1 + t.n2 << endl;
}

time_t start, end;
double diff;

int main(int argc, char* argv[]) 
{
    time(&start);
    multi_thread();
    time(&end);
    diff=difftime(end, start);
    cout<<diff<<" seconds elapsed for multi thread calculation."<<endl;

    time(&start);
    one_thread();
    time(&end);
    diff=difftime(end, start);
    cout<<diff<<" seconds elapsed for 1 thread calculation."<<endl;
    return 0;
}