title: Program stalls during long runs
body: <p>Fixed:</p>
  
  <p>Well this seems a bit silly. Turns out top was not displaying correctly and programs actually continue to run. Perhaps the CPU time became too large to display? Either way, the program seems to be working fine and this whole question was moot.</p>
  
  <p>Thanks (and sorry for the silly question).</p>
  
  <p>Original Q:</p>
  
  <p>I am running a simulation on a computer running Ubuntu server 10.04.3. Short runs (&lt;24 hours) run fine, but long runs eventually stall. By stall, I mean that the program no longer gets any CPU time, but it still holds all information in memory. In order to run these simulations, I SSH and nohup the program and pipe any output to a file.</p>
  
  <p>Miscellaneous information:</p>
  
  <p>The system is definitely not running out of RAM. The program does not need to read or write to the hard drive until completion; the computation is done completely in memory. The program is not killed, as it still has a PID after it stalls. I am using openmp, but have increased the max number of processes and the max time is unlimited. I am finding the largest eigenvalues of a matrix using the ARPACK fortran library.</p>
  
  <p>Any thoughts on what is causing this behavior or how to resume my currently stalled program?</p>
  
  <p>Thanks</p>