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

   # xcallsbypid.d
   Tracing... Hit Ctrl-C to end.
   ^C
      PID CMD                        XCALLS
      215 utmpd                           3
     6350 bash                            3
     6351 bash                            3
     6350 ls                             24
        0 sched                          48
     6349 dtrace                         93
     6351 find                         5718

In the above output, we can see the find command with PID 6351 has caused
5718 cross calls.