title: C++ How to force prefetch data to cache? (array loop)
body: <p>I have loop like this</p>
  
  <pre><code>start = __rdtsc();
  unsigned long long count = 0;
  for(int i = 0; i &lt; N; i++)
      for(int j = 0; j &lt; M; j++)
          count += tab[i][j];
  stop = __rdtsc();
  time = (stop - start) * 1/3;
  </code></pre>
  
  <p>Need to check how prefetch data influences on efficiency.  How to force prefetch some values from memory into cache before they will be counted?</p>