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PROFIL(2) | 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,
vm_offset_t
offset, int
scale);
DESCRIPTION¶
Theprofil
() system call enables or disables
program counter profiling of the current process. If profiling is enabled,
then at every profiling clock tick, the kernel updates an appropriate count in
the samples buffer. The frequency of the
profiling clock is recorded in the header in the profiling output file.
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 profiling 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
RETURN VALUES¶
Theprofil
() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate
the error.
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¶
Theprofil
() function appeared in
Version 7 AT&T UNIX.
BUGS¶
This routine should be namedprofile
().
The samples argument should really be a vector
of type unsigned short.
The format of the gmon.out file is undocumented.June 4, 1993 | Debian |