2.11BSD#431 - /usr/man/cat3/monitor.0

MONITOR(3)	    UNIX Programmer's Manual	       MONITOR(3)


NAME
     monitor, monstartup, moncontrol - prepare execution profile

SYNOPSIS
     monitor(lowpc, highpc, buffer, bufsize, nfunc)
     int (*lowpc)(), (*highpc)();
     short buffer[];

     monstartup(lowpc, highpc)
     int (*lowpc)(), (*highpc)();

     moncontrol(mode)

DESCRIPTION
     There are two different forms of monitoring available: An
     executable program created by:

	  cc -p . . .

     automatically includes calls for the prof(1) monitor and
     includes an initial call to its start-up routine monstartup
     with default parameters; monitor need not be called expli-
     citly except to gain fine control over profil buffer alloca-
     tion.  An executable program created by:

	  cc -pg . . .

     automatically includes calls for the gprof(1) monitor.

     Monstartup is a high level interface to profil(2).  Lowpc
     and highpc specify the address range that is to be sampled;
     the lowest address sampled is that of lowpc and the highest
     is just below highpc.  Monstartup allocates space using
     sbrk(2) and passes it to monitor (see below) to record a
     histogram of periodically sampled values of the program
     counter, and of counts of calls of certain functions, in the
     buffer.  Only calls of functions compiled with the profiling
     option -p of cc(1) are recorded.

     To profile the entire program, it is sufficient to use

	  extern etext();
	  . . .
	  monstartup((int) 2, etext);

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

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

	  monitor(0);


Printed 11/26/99	  May 15, 1985				1


MONITOR(3)	    UNIX Programmer's Manual	       MONITOR(3)


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

     Moncontrol is used to selectively control profiling within a
     program.  This works with either prof(1) or gprof(1) type
     profiling.  When the program starts, profiling begins.  To
     stop the collection of histogram ticks and call counts use
     moncontrol(0); to resume the collection of histogram ticks
     and call counts use moncontrol(1).  This allows the cost of
     particular operations to be measured.  Note that an output
     file will be produced upon program exit irregardless of the
     state of moncontrol.

     Monitor is a low level interface to profil(2).  Lowpc and
     highpc are the addresses of two functions; buffer is the
     address of a (user supplied) array of bufsize short
     integers.	At most nfunc call counts can be kept.	For the
     results to be significant, especially where there are small,
     heavily used routines, it is suggested that the buffer be no
     more than a few times smaller than the range of locations
     sampled.  Monitor divides the buffer into space to record
     the histogram of program counter samples over the range
     lowpc to highpc, and space to record call counts of func-
     tions compiled with the -p option to cc(1).

     To profile the entire program, it is sufficient to use

	  extern etext();
	  . . .
	  monitor((int) 2, etext, buf, bufsize, nfunc);

FILES
     mon.out

SEE ALSO
     cc(1), prof(1), gprof(1), profil(2), sbrk(2)


Printed 11/26/99	  May 15, 1985				2