profile ?-commands? on
              profile off arrayVar
              This  command is used to collect a performance pro-
              file of a Tcl script.  It collects data at the  Tcl
              procedure  level.  The  number of calls to a proce-
              dure, and the amount of real and CPU time  is  col-
              lected.  Time is also collected for the global con-
              text.  The procedure data is collected by bucketing
              it  based  on the procedure call stack, this allows
              determination of how much time is spent in  a  par-
              ticular procedure in each of it's calling contexts.

              The on option enables profile data  collection.  If
              the  -commands option is specifed, data on all com-
              mands within a procedure is  collected  as  well  a
              procedures.   Multiple  occurrences  of  a  command
              within a procedure are not distinguished, but  this
              data may still be useful for analysis.

              The  off  option  turns off profiling and moves the
              data collected to the array arrayVar.  The array is
              address  by  a  list  containing the procedure call
              stack.  Element zero is the top of the  stack,  the
              procedure  that  the data is for.  The data in each
              entry is a list consisting of  the  procedure  call
              count  and  the real time and CPU time in millisec-
              onds spent in the procedure (and all procedures  it
              called).  The list is in the form {count real cpu}.
              A Tcl procedure profrep is  supplied  for  reducing
              the data and producing a report

              This command is provided by Extended Tcl.