profil(2) [osx man page]

PROFIL(2)						      BSD System Calls Manual							 PROFIL(2)

NAME

     profil -- control process profiling

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     int
     profil(char *samples, size_t size, u_long offset, u_int scale);

DESCRIPTION

     -- This function is now deprecated. It will always return EINVAL. --

     The intended replacements are the user-level developer tools, like CHUD and dtrace.

     ------

     The profil() function enables or disables program counter profiling of the current process.  If profiling is enabled, then at every clock
     tick, the kernel updates an appropriate count in the samples buffer.

     The buffer samples contains size bytes and is divided into a series of 16-bit bins.  Each bin counts the number of times the program counter
     was in a particular address range in the process when a clock tick occurred while profiling was enabled.  For a given program counter
     address, the number of the corresponding bin is given by the relation:

	   [(pc - offset) / 2] * scale / 65536

     The offset parameter is the lowest address at which the kernel takes program counter samples.  The scale parameter ranges from 1 to 65536 and
     can be used to change the span of the bins.  A scale of 65536 maps each bin to 2 bytes of address range; a scale of 32768 gives 4 bytes,
     16384 gives 8 bytes and so on.  Intermediate values provide approximate intermediate ranges.  A scale value of 0 disables profiling.

RETURN VALUES

     If the scale value is nonzero and the buffer samples contains an illegal address, profil() returns -1, profiling is terminated and errno is
     set appropriately.  Otherwise profil() returns 0.

FILES

     /usr/lib/gcrt0.o  profiling C run-time startup file
     gmon.out	       conventional name for profiling output file

ERRORS

     The following error may be reported:

     [EFAULT]		The buffer samples contains an invalid address.

SEE ALSO

     gprof(1)

HISTORY

     The profil() function appeared in Version 7 AT&T UNIX.

BUGS

     This routine should be named profile().

     The samples argument should really be a vector of type unsigned short.

     The format of the gmon.out file is undocumented.

BSD
								September 26, 2008							       BSD

Check Out this Related Man Page

PROFIL(3)						     Linux Programmer's Manual							 PROFIL(3)

NAME

       profil - execution time profile

SYNOPSIS

       #include <unistd.h>

       int profil(unsigned short *buf, size_t bufsiz,
		  size_t offset, unsigned int scale);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       profil():
	   Since glibc 2.21:
	       _DEFAULT_SOURCE
	   In glibc 2.19 and 2.20:
	       _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
	   Up to and including glibc 2.19:
	       _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION

       This  routine  provides a means to find out in what areas your program spends most of its time.	The argument buf points to bufsiz bytes of
       core.  Every virtual 10 milliseconds, the user's program counter (PC) is examined: offset is subtracted and the	result	is  multiplied	by
       scale  and  divided  by	65536.	If the resulting value is less than bufsiz, then the corresponding entry in buf is incremented.  If buf is
       NULL, profiling is disabled.

RETURN VALUE

       Zero is always returned.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +----------+---------------+-----------+
       |Interface | Attribute	  | Value     |
       +----------+---------------+-----------+
       |profil()  | Thread safety | MT-Unsafe |
       +----------+---------------+-----------+

CONFORMING TO

       Similar to a call in SVr4 (but not POSIX.1).

BUGS

       profil() cannot be used on a program that also uses ITIMER_PROF interval timers (see setitimer(2)).

       True kernel profiling provides more accurate results.  Libc 4.4 contained a kernel patch providing a system call profil.

SEE ALSO

       gprof(1), sprof(1), setitimer(2), sigaction(2), signal(2)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15								 PROFIL(3)

Linux and UNIX Man Pages

profil(2) [osx man page]

Check Out this Related Man Page