| .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
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| .\" permission notice identical to this one. |
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| .\" Since the Linux kernel and libraries are constantly changing, this |
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| .\" |
| .\" Modified Fri Jun 23 01:35:19 1995 Andries Brouwer <aeb@cwi.nl> |
| .\" (prompted by Bas V. de Bakker <bas@phys.uva.nl>) |
| .\" Corrected (and moved to man3), 980612, aeb |
| .TH PROFIL 3 2021-03-22 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| profil \- execution time profile |
| .SH SYNOPSIS |
| .nf |
| .B #include <unistd.h> |
| .PP |
| .BI "int profil(unsigned short *" buf ", size_t " bufsiz , |
| .BI " size_t " offset ", unsigned int " scale ); |
| .PP |
| .fi |
| .RS -4 |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .RE |
| .PP |
| .BR profil (): |
| .nf |
| Since glibc 2.21: |
| .\" commit 266865c0e7b79d4196e2cc393693463f03c90bd8 |
| _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) |
| .fi |
| .SH DESCRIPTION |
| This routine provides a means to find out in what areas your program |
| spends most of its time. |
| The argument |
| .I buf |
| points to |
| .I bufsiz |
| bytes of core. |
| Every virtual 10 milliseconds, the user's program counter (PC) |
| is examined: |
| .I offset |
| is subtracted and the result is multiplied by |
| .I scale |
| and divided by 65536. |
| If the resulting value is less than |
| .IR bufsiz , |
| then the corresponding entry in |
| .I buf |
| is incremented. |
| If |
| .I buf |
| is NULL, profiling is disabled. |
| .SH RETURN VALUE |
| Zero is always returned. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR profil () |
| T} Thread safety MT-Unsafe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| Similar to a call in SVr4 (but not POSIX.1). |
| .SH BUGS |
| .BR profil () |
| cannot be used on a program that also uses |
| .B ITIMER_PROF |
| interval timers (see |
| .BR setitimer (2)). |
| .PP |
| True kernel profiling provides more accurate results. |
| .\" Libc 4.4 contained a kernel patch providing a system call profil. |
| .SH SEE ALSO |
| .BR gprof (1), |
| .BR sprof (1), |
| .BR setitimer (2), |
| .BR sigaction (2), |
| .BR signal (2) |