NAME

monitor, monstartup − prepare execution profile

SYNOPSIS

monitor(lowpc, highpc, buffer, bufsize, nfunc)
int (∗lowpc)(), (∗highpc)();
short buffer[];
 monstartup(lowpc, highpc)
int (∗lowpc)(), (∗highpc)();

DESCRIPTION

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

cc −p . . .

automatically includes calls for monstartup with default parameters; monitor need not be called explicitly except to gain fine control over profiling.  An executable program created by:

cc −pg . . .

obtains a different 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);

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

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 functions 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)

Sun System Release 0.3  —  4 March 1983