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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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2007-04-12 22:42:49 +00:00
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.\"
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2004-11-03 13:51:07 +00:00
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" Modified Fri Jun 23 01:35:19 1995 Andries Brouwer <aeb@cwi.nl>
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.\" (prompted by Bas V. de Bakker <bas@phys.uva.nl>)
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.\" Corrected (and moved to man3), 980612, aeb
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2007-07-08 12:11:40 +00:00
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.TH PROFIL 3 2007-07-26 "Linux" "Linux Programmer's Manual"
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.SH NAME
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profil \- execution time profile
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.SH SYNOPSIS
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.B #include <unistd.h>
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.sp
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2007-12-23 17:26:26 +00:00
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.BI "int profil(unsigned short *" buf ", size_t " bufsiz \
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", size_t " offset ", unsigned int " scale );
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR profil ():
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_BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\ <\ 500)
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.SH DESCRIPTION
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This routine provides a means to find out in what areas your program
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spends most of its time.
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The argument
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.I buf
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points to
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.I bufsiz
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bytes of core.
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Every virtual 10 milliseconds, the user's program counter (PC)
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is examined:
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.I offset
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is subtracted and the result is multiplied by
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2007-09-20 16:26:31 +00:00
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.I scale
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and divided by 65536.
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If the resulting value is less than
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.IR bufsiz ,
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then the corresponding entry in
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.I buf
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is incremented.
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If
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.I buf
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is NULL, profiling is disabled.
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.SH "RETURN VALUE"
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Zero is always returned.
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2007-05-19 04:30:20 +00:00
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.SH "CONFORMING TO"
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Similar to a call in SVr4 (but not POSIX.1-2001).
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.SH BUGS
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2005-10-19 06:54:38 +00:00
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.BR profil ()
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cannot be used on a program that also uses
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.B ITIMER_PROF
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2008-07-12 21:01:09 +00:00
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interval timers (see
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.BR setitimer (2)).
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2004-11-03 13:51:07 +00:00
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True kernel profiling provides more accurate results.
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Libc 4.4 contained a kernel patch providing a system call profil.
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.SH "SEE ALSO"
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.BR gprof (1),
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.BR setitimer (2),
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.BR sigaction (2),
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.BR signal (2)
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