The following is a demonstration of the syscallbysysc.d script,

   # syscallbysysc.d
   dtrace: description 'syscall:::entry ' matched 228 probes
   ^C
     fstat                                                             1
     setcontext                                                        1
     lwp_park                                                          1
     schedctl                                                          1
     mmap                                                              1
     sigaction                                                         2
     pset                                                              2
     lwp_sigmask                                                       2
     gtime                                                             3
     sysconfig                                                         3
     write                                                             4
     brk                                                               6
     pollsys                                                           7
     p_online                                                        558
     ioctl                                                           579

In the above output, the ioctl system call was the most common, occuring
579 times.