monitor(3C) monitor(3C)
NAME
monitor - prepare execution profile
SYNOPSIS
#include <mon.h>
void monitor (int (*lowpc)(), int (*highpc)(), WORD *buffer,
size_t bufsize, size_t nfunc);
DESCRIPTION
monitor is an interface to profil.
When used, monitor is called at least at the beginning and the
end of a program. The first call to monitor initiates the
recording of two different kinds of execution-profile
information: execution-time distribution and function call
count. Execution-time distribution data is generated by
profil and the function call counts are generated by code
supplied to the object file (or files) by cc -p. Both types
of information are collected as a program executes. The last
call to monitor writes this collected data to the output file
mon.out.
lowpc and highpc are the beginning and ending addresses of the
region to be profiled.
buffer is the address of a user-supplied array of WORD (WORD
is defined in the header file mon.h). buffer is used by
monitor to store the histogram generated by profil and the
call counts.
bufsize identifies the number of array elements in buffer.
nfunc is the number of call count cells that have been
reserved in buffer. Additional call count cells will be
allocated automatically as they are needed.
bufsize should be computed using the following formula:
size_of_buffer =
sizeof(struct hdr) +
nfunc * sizeof(struct cnt) +
((highpc-lowpc)/BARSIZE) * sizeof(WORD) +
sizeof(WORD) - 1 ;
Copyright 1994 Novell, Inc. Page 1
monitor(3C) monitor(3C)
bufsize = (size_of_buffer / sizeof(WORD)) ;
where:
lowpc, highpc, nfunc are the same as the arguments to
monitor;
BARSIZE is the number of program bytes that correspond
to each histogram bar, or cell, of the profil buffer;
the hdr and cnt structures and the type WORD are defined
in the header file mon.h.
An example call to monitor is shown below:
monitor (&eprol, &etext, wbuf, wbufsz, 600);
where:
eprol is the beginning of the user's program;
etext is the end of the user's program [see end(3C)];
wbuf is an array of WORD with wbufsz elements;
wbufsz
is computed using the bufsize formula shown above with
BARSIZE of 8;
600 is the number of call count cells that have been
reserved in buffer.
These parameter settings establish the computation of an
execution-time distribution histogram that uses profil for the
entire program, initially reserves room for 600 call count
cells in buffer, and provides for enough histogram cells to
generate significant distribution-measurement results. [For
more information on the effects of bufsize on execution-
distribution measurements, see profil(2).]
To stop execution monitoring and write the results to a file,
use the following:
monitor((int (*)())0, (int (*)())0, (WORD *)0, 0, 0);
Copyright 1994 Novell, Inc. Page 2
monitor(3C) monitor(3C)
Use prof to examine the results.
Files
mon.out
REFERENCES
cc(1), end(3C), prof(1), profil(2)
NOTICES
Additional calls to monitor after main has been called and
before exit has been called will add to the function-call
count capacity, but such calls will also replace and restart
the profil histogram computation.
The name of the file written by monitor is controlled by the
environment variable PROFDIR. If PROFDIR does not exist, the
file mon.out is created in the current directory. If PROFDIR
exists but has no value, monitor does no profiling and creates
no output file. If PROFDIR is dirname, and monitor is called
automatically by compilation with cc -p, the file created is
dirname/pid.progname where progname is the name of the
program.
Copyright 1994 Novell, Inc. Page 3