title: Surefire forkCount not resulting in this number of processes
body: <p>I can set the value of the parameter <code>forkCount</code> to any desired number, say 12, and I'd expect to have 12 new Java processes of type <code>surefirebooter</code> when running tests like these.  But <code>ps</code> shows that I only <em>sometimes</em> get the 12 expected Java processes (to be precise: I get them extremely rarely).  Instead I typically get less, sometimes even only three or four.  Execution of my hundreds of unit tests also appears to be slow then.</p>
  
  <p>The running processes also often disappear from the <code>ps</code> output (terminate, I assume) before the unit tests are done.  In some cases <em>all</em> of them, then the execution hangs indefinitely.</p>
  
  <p>Documentation wasn't too clear about this, but I'd expect to have the given number of processes all the time until all unit tests are done.</p>
  
  <p>Maybe the <code>surefirebooter</code> processes run into some problem and terminate prematurely.  I see no error message, though.  Where should I see them?  Can I switch on some debug logging?  Switching on the debug mode of Surefire changed the test results, so I didn't follow that path very far.</p>
  
  <p>I'm running ~1600 unit tests in ~400 classes which takes ~7 minutes in the best case.  Execution time varies greatly, sometimes the whole thing terminates after more than an hour.</p>
  
  <p>In some cases, on the other hand, the <code>surefirebooter</code> processes continue to run after execution finished (successfully) and puts massive load on the system (so it seems to be busy waiting for something).</p>
  
  <p>Questions:</p>
  
  <ul>
  <li>Can anybody explain these observed phenomena?</li>
  <li>Can anybody give advice what to change in order to have a more proper execution?  (I. e. with the desired number of <code>surefirebooter</code> processes at all times.)</li>
  <li>Can anybody give advice on how to debug the situation?  See messages about what happens with the <code>surefirebooter</code> processes?  (I tried using <code>strace</code> but that also changed the behavior so dramatically that the call didn't terminate anymore.)</li>
  </ul>