- "active" in detailed output is now slightly more meaningful.
    It is > 0 only if other requests started after it started
    but before it finished.  The greater the active count, the
    more likely it is that something was going on at the time
    in which the request ran that caused a slowdown.


  - multiple files may be analyzed at the same time.

Also, script recognizes "U" opcode in big M logs as meaning a restart.