$ time perl -MRemote::Use=config,rsyncconfig prime3.pl
  receiving file list ... done
  >f+++++++++ XS.so

  sent 42 bytes  received 16141 bytes  10788.67 bytes/sec
  total size is 16043  speedup is 0.99
  receiving file list ... done
  >f+++++++++ XS.bs

  sent 42 bytes  received 94 bytes  90.67 bytes/sec
  total size is 0  speedup is 0.00
  receiving file list ... done
  >f+++++++++ XS.pm

  sent 42 bytes  received 5733 bytes  11550.00 bytes/sec
  total size is 5635  speedup is 0.98
  2 3 5 7
  5 7

  real    0m2.349s
  user    0m0.116s
  sys     0m0.060s