1.\" Copyright (c) 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Donn Seeley of BSDI. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)profil.2 8.1 (Berkeley) 6/4/93 36.\" $FreeBSD: src/lib/libc/sys/profil.2,v 1.9.2.3 2001/12/14 18:34:01 ru Exp $ 37.\" $DragonFly: src/lib/libc/sys/profil.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 38.\" 39.Dd June 4, 1993 40.Dt PROFIL 2 41.Os 42.Sh NAME 43.Nm profil 44.Nd control process profiling 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In unistd.h 49.Ft int 50.Fn profil "char *samples" "size_t size" "vm_offset_t offset" "int scale" 51.Sh DESCRIPTION 52The 53.Fn profil 54function enables or disables 55program counter profiling of the current process. 56If profiling is enabled, 57then at every profiling clock tick, 58the kernel updates an appropriate count in the 59.Fa samples 60buffer. 61The frequency of the profiling clock is recorded 62in the header in the profiling output file. 63.Pp 64The buffer 65.Fa samples 66contains 67.Fa size 68bytes and is divided into 69a series of 16-bit bins. 70Each bin counts the number of times the program counter 71was in a particular address range in the process 72when a profiling clock tick occurred while profiling was enabled. 73For a given program counter address, 74the number of the corresponding bin is given 75by the relation: 76.Bd -literal -offset indent 77[(pc - offset) / 2] * scale / 65536 78.Ed 79.Pp 80The 81.Fa offset 82parameter is the lowest address at which 83the kernel takes program counter samples. 84The 85.Fa scale 86parameter ranges from 1 to 65536 and 87can be used to change the span of the bins. 88A scale of 65536 maps each bin to 2 bytes of address range; 89a scale of 32768 gives 4 bytes, 16384 gives 8 bytes and so on. 90Intermediate values provide approximate intermediate ranges. 91A 92.Fa scale 93value of 0 disables profiling. 94.Sh RETURN VALUES 95.Rv -std profil 96.Sh FILES 97.Bl -tag -width /usr/lib/gcrt0.o -compact 98.It Pa /usr/lib/gcrt0.o 99profiling C run-time startup file 100.It Pa gmon.out 101conventional name for profiling output file 102.El 103.Sh ERRORS 104The following error may be reported: 105.Bl -tag -width Er 106.It Bq Er EFAULT 107The buffer 108.Fa samples 109contains an invalid address. 110.El 111.Sh SEE ALSO 112.Xr gprof 1 113.Sh HISTORY 114A 115.Fn profil 116function call appeared in 117.At v7 . 118.Sh BUGS 119This routine should be named 120.Fn profile . 121.Pp 122The 123.Fa samples 124argument should really be a vector of type 125.Fa "unsigned short" . 126.Pp 127The format of the gmon.out file is undocumented. 128