title: How to limit the number of processors that Python uses
body: <p>I have a fairly memory expensive Python program to run on a computer that has 8 CPUs (using Python 3.1 64 bit). The problem is that it uses all 8 processors to 100% usage and thus freezes the machine and makes things slow. How would I make Python use only 7 of the processors to free up more CPU? I have experimented with the Pool class within the multiprocessing library many times, but no luck. </p>
  
  <p>For instance, if I want to call the main function of my program and have it use only 7 processors, it seems like all I would have to do is the following, but no luck:</p>
  
  <p>from multiprocessing import Pool
  Pool(7, main())</p>
  
  <p>Can anybody tell me where I am going wrong?  Thanks!  </p>