Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #561
Difficulty: Easy
GDB is a command line debugger.
True or False?
Linux & Unix Commands - Search Man Pages

monstartup(3) [bsd man page]

MONITOR(3)						     Library Functions 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 parame- ters; monitor need not be called explicitly except to gain fine control over profil buffer allocation. 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); 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 sup- plied) 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) 4th Berkeley Distribution May 15, 1985 MONITOR(3)

Check Out this Related Man Page

monitor(3)						     Library Functions 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
       These functions use the system call to control program-counter sampling.  Using the option -p when compiling or linking a program automati-
       cally generates calls to these functions.  You do need not to call these functions explicitly unless you want more control.

       Typically, you would call either or to initialize pc-sampling and enable it; call to disable or reenable it; and call at the end of  execu-
       tion to disable sampling and record the samples in a file.

       Your  initial  call  to	enables  pc-sampling.	The  parameters lowpc and highpc specify the range of addresses to be sampled.	The lowest
       address is that of lowpc and the highest is just below highpc.  The buffer parameter is the address of a (user allocated) array of  bufsize
       short  integers,  which	holds  a  record of the samples; for best results, the buffer should not be less than a few times smaller than the
       range of addresses sampled.  The nfunc parameter is ignored.

       The environment variable PROFDIR determines the name of the output file and whether pc-sampling takes place: if it is not set, the file	is
       named  mon.out;	if  set  to  the empty string, no pc-sampling occurs; if set to a non-empty string, the file is named string/pid.progname,
       where pid is the process id of the executing program and progname is the program's name as it appears in argv[0]. The  subdirectory  string
       must already exist.

       To profile the entire program, use the following:

	    extern eprol(), etext();
	    . . .
	    monitor(eprol, etext, buf, bufsize, 0);

       The  routine  lies just below the user program text, and lies just above it, as described in (Because the user program does not necessarily
       start at a low memory address, using a small number in place of is dangerous).

       The routine is an alternate form of that calls (see for you to allocate the buffer.

       The function selectively disables and re-enables pc-sampling within a program, allowing you to measure the cost of  particular  operations.
       The function disables pc-sampling, and reenables it.

       To stop execution monitoring and write the results in the output file, use the following:

	    monitor(0);

Files
       mon.out	     default name for output file
       libprof1.a    routines for pc-sampling

See Also
       cc(1), ld(1), profil(2), brk(2)

								       RISC								monitor(3)

Featured Tech Videos