title: Basic 2-dimensional graph with gnuplot
body: <p>I have the followint txt file:</p>
  
  <pre><code># tlb_size  AMAT    tlb_miss_rate
  2   2918.67 19.85
  4   2905.33 13.20
  8   2900.00 10.50
  16  2892.33 6.60
  32  2884.33 2.71
  64  2881.00 0.93
  128 2880.00 0.56
  256 2879.67 0.41
  512 2879.67 0.36
  1024    2879.67 0.33
  2048    2879.67 0.27
  4096    2879.67 0.27
  </code></pre>
  
  <p>I want to plot 2 curves on one 2-dimensional graph: of AMAT as a function of tlb_size and the second curve tlb_miss_rate as a function of (also) tlb_size. 
  The x-asis being the tlb_size, the y-axis being AMAT and  tlb_size, hopefully for some normal scale.</p>
  
  <p>It is very basic but I can't find the solution. Please help. </p>