game.cpp
--------

#include <iostream>
#include <cmath>
#include <chrono>

template<typename TimeT = std::chrono::microseconds>
struct measure
{
    template<typename F, typename ...Args>
    static typename TimeT::rep execution(F&& func, Args&&... args)
    {
        auto start = std::chrono::steady_clock::now();
        std::forward<decltype(func)>(func)(std::forward<Args>(args)...);
        auto duration = std::chrono::duration_cast< TimeT>
                            (std::chrono::steady_clock::now() - start);
        return duration.count();
    }
};

using namespace std;

class Player {
  public:
  float x;
  float y;
  float dx;
  float dy;
};

const int PLAYERS = 100000000;
const int N = 1;
Player pls[PLAYERS];

void seq(Player pls[], int n) {
  for (int i=0;i<n;i++) {
    for (int j=0;j<N;j++) {
      pls[i].x += std::sin(2 * M_PI * i * j * pls[i].dx);
      pls[i].y += std::sin(2 * M_PI * i * j * pls[i].dy);
    }
  }
}
void par(Player pls[], int n) {
  #pragma omp parallel for
  for (int i=0;i<n;i++) {
    for (int j=0;j<N;j++) {
      pls[i].x += std::sin(2 * M_PI * i * j * pls[i].dx);
      pls[i].y += std::sin(2 * M_PI * i * j * pls[i].dy);
    }
  }
}

int main() {
  cout << "players, seq, par" << endl;
  for (int i=1000;i<PLAYERS;i<<=1) {
    cout << i << ", " << measure<>::execution(seq, pls, i) << ", " << measure<>::execution(par, pls, i) << endl;
  }
}

game.r
------
library(ggplot2)
g = read.csv("game.csv")
ggplot(g) + geom_line(stat="identity", aes(players, par, color="par"))+ geom_line(stat="identity", aes(players, seq, color="seq")) + scale_y_continuous(name='runtime', trans='log2') + scale_x_continuous(name='players',trans='log2')
ggsave("game.png")