monitor(3c)                DG/UX 4.30                 monitor(3c)



     NAME
          monitor - prepare execution profile

     SYNOPSIS
          #include <mon.h>

          void monitor (lowpc, highpc, buffer, bufsize, nfunc)
          int (*lowpc)( ), (*highpc)( );
          WORD *buffer;
          int bufsize, nfunc;

     DESCRIPTION
          Monitor is an interface to profil(2).  Lowpc and highpc are
          the addresses of two functions; buffer is the address of a
          (user-supplied) array of bufsize WORDs (defined in the
          <mon.h> header file).  Monitor arranges to record a
          histogram of periodically sampled values of the program
          counter, and counts of calls of certain functions, in the
          buffer.  The lowest address sampled is that of lowpc and the
          highest is just below highpc.  Lowpc may not equal 0 for
          this use of monitor.  At most nfunc call counts can be kept;
          only calls of functions compiled for profiling, as with the
          -p option of cc(1), are recorded.

          An executable program created using the -p option with cc
          automatically includes calls for monitor with default
          parameters; you need not call monitor explicitly except to
          gain fine control over profiling.

          Space in the buffer is divided among a header (sizeof(struct
          hdr) bytes), call counts (nfunc * sizeof(struct cnt) bytes),
          and pc counts (the remainder, taken as an array of WORDs).
          On a machine whose instructions are 32 bits in size (such as
          the MC88000), a pc counts area half the size of the profiled
          region (((unsigned) highpc - (unsigned) lowpc) / 2) allows
          for each instruction to have its own count, thereby
          maximizing precision.  Providing space for fewer pc counts
          results in less precision.

          For the results to be significant, especially where there
          are small, heavily used routines, bufsize should be computed
          using definitions from the <mon.h> header file as follows:

          To profile the entire program, it is sufficient to use:

               extern etext();
               ...
               monitor ((int (*)())4, etext, buf, bufsize, nfunc);

          where bufsize is:

               (sizeof(struct hdr) +



     Licensed material--property of copyright holder(s)         Page 1

     monitor(3c)                DG/UX 4.30                 monitor(3c)



                (nfunc * sizeof(struct cnt)) +
                (((unsigned)etext - 4) / 2))
               / sizeof(WORD)

          and buf is an array of bufsize * sizeof(WORD) bytes.

          Etext lies just above all the program text; see end(3C).

          To stop execution monitoring and write the results on the
          file mon.out, use

               monitor ((int (*)())0, (int (*)())0, 0, 0, 0);

          Prof(1) can then be used to examine the results.

     FILES
          mon.out
          /lib/libp/libc.a
          /lib/libp/libm.a

     SEE ALSO
          profil(2), end(3C).
          cc(1), prof(1) in the User's Reference for the DG/UX System
































     Licensed material--property of copyright holder(s)         Page 2