1.\" $NetBSD: profil.2,v 1.3 1995/11/22 23:07:23 cgd Exp $ 2.\" 3.\" Copyright (c) 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Donn Seeley of BSDI. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the University of 20.\" California, Berkeley and its contributors. 21.\" 4. Neither the name of the University nor the names of its contributors 22.\" may be used to endorse or promote products derived from this software 23.\" without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" @(#)profil.2 8.1 (Berkeley) 6/4/93 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 SYNOPSIS 46.Ft int 47.Fn profil "char *samples" "size_t size" "u_long offset" "u_int scale" 48.Sh DESCRIPTION 49The 50.Fn profil 51function enables or disables 52program counter profiling of the current process. 53If profiling is enabled, 54then at every clock tick, 55the kernel updates an appropriate count in the 56.Fa samples 57buffer. 58.Pp 59The buffer 60.Fa samples 61contains 62.Fa size 63bytes and is divided into 64a series of 16-bit bins. 65Each bin counts the number of times the program counter 66was in a particular address range in the process 67when a clock tick occurred while profiling was enabled. 68For a given program counter address, 69the number of the corresponding bin is given 70by the relation: 71.Bd -literal -offset indent 72[(pc - offset) / 2] * scale / 65536 73.Ed 74.Pp 75The 76.Fa offset 77parameter is the lowest address at which 78the kernel takes program counter samples. 79The 80.Fa scale 81parameter ranges from 1 to 65536 and 82can be used to change the span of the bins. 83A scale of 65536 maps each bin to 2 bytes of address range; 84a scale of 32768 gives 4 bytes, 16384 gives 8 bytes and so on. 85Intermediate values provide approximate intermediate ranges. 86A 87.Fa scale 88value of 0 disables profiling. 89.Sh RETURN VALUES 90If the 91.Fa scale 92value is nonzero and the buffer 93.Fa samples 94contains an illegal address, 95.Fn profil 96returns \-1, 97profiling is terminated and 98.Va errno 99is set appropriately. 100Otherwise 101.Fn profil 102returns 0. 103.Sh FILES 104.Bl -tag -width /usr/lib/gcrt0.o -compact 105.It Pa /usr/lib/gcrt0.o 106profiling C run-time startup file 107.It Pa gmon.out 108conventional name for profiling output file 109.El 110.Sh ERRORS 111The following error may be reported: 112.Bl -tag -width Er 113.It Bq Er EFAULT 114The buffer 115.Fa samples 116contains an invalid address. 117.El 118.Sh SEE ALSO 119.Xr gprof 1 120.\" .Sh HISTORY 121.\" wish I knew... probably v7. 122.Sh BUGS 123This routine should be named 124.Fn profile . 125.Pp 126The 127.Fa samples 128argument should really be a vector of type 129.Fa "unsigned short" . 130.Pp 131The format of the gmon.out file is undocumented. 132