data locality - slow example, C++ (gcc)

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//https://www.youtube.com/watch?v=TJHgp1ugKGM

//g++  5.4.0

#include <iostream>
#include <vector>

class AIComponent
{
    public:
      void update() { /* Work with and modify state... */ }
    
    private:
      // Goals, mood, etc. ...
};

class PhysicsComponent
{
    public:
      void update() { /* Work with and modify state... */ }
    
    private:
      // Rigid body, velocity, mass, etc. ...
};

class RenderComponent
{
    public:
      void render() { /* Work with and modify state... */ }
    
    private:
      // Mesh, textures, shaders, etc. ...
};

class GameEntity
{
    public:
      GameEntity(AIComponent* ai,
                 PhysicsComponent* physics,
                 RenderComponent* render)
      : ai_(ai), physics_(physics), render_(render)
      {}
    
      AIComponent* ai() { return ai_; }
      PhysicsComponent* physics() { return physics_; }
      RenderComponent* render() { return render_; }

private:
      AIComponent* ai_;
      PhysicsComponent* physics_;
      RenderComponent* render_;
};

int main()
{
    std::vector<GameEntity> entities;
    int total = 10000000;
    for(int i=0; i<total; i++)
    {
        auto ge = GameEntity(new AIComponent(), new PhysicsComponent(), new RenderComponent());
        entities.push_back(ge);
    }
    
    for(auto& e: entities)
    {
        e.ai()->update();
    }
    for(auto& e: entities)
    {
        e.physics()->update();
    }
    for(auto& e: entities)
    {
        e.render()->render();
    }

}

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Compilation time: 0.42 sec, absolute running time: 1.84 sec, cpu time: 1.71 sec, memory peak: 1153 Mb, absolute service time: 2,27 sec