usage is:

   valgrind-di-server [--exit-at-zero|-e] [port-number]

   where   --exit-at-zero or -e causes the listener to exit
           when the number of connections falls back to zero
           (the default is to keep listening forever)

           --max-connect=INT can be used to increase the maximum
           number of connected processes (default = 50).
           INT must be positive and less than 5000.

           port-number is the default port on which to listen for
           connections.  It must be between 1024 and 65535.
           Current default is 1500.