title: Which real-time priority is the highest priority in Linux
body: <p>In the Linux real-time process priority range 1 to 99, it's unclear to me which is the highest priority, 1 or 99.  </p>
  
  <p>Section 7.2.2 of "Understanding the Linux Kernel" (O'Reilly) says 1 is the highest priority, which makes sense considering that normal processes have static priorities from 100 to 139, with 100 being the highest priority:  </p>
  
  <blockquote>
    <p>"Every real-time process is associated with a real-time priority, which is a value ranging from 1 (highest
    priority) to 99 (lowest priority). "</p>
  </blockquote>
  
  <p>On the other hand, the sched_setscheduler man page (RHEL 6.1) claims that 99 is the highest:</p>
  
  <blockquote>
    <p>"Processes  scheduled  under  one  of the real-time policies (SCHED_FIFO, SCHED_RR)
           have a sched_priority value in the range 1 (low) to 99 (high)."</p>
  </blockquote>
  
  <p>Which is the highest real-time priority?</p>