.\" $NetBSD: profil.2,v 1.3 1995/11/22 23:07:23 cgd Exp $ .\" .\" Copyright (c) 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Donn Seeley of BSDI. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)profil.2 8.1 (Berkeley) 6/4/93 .\" .Dd September 26, 2008 .Dt PROFIL 2 .Os .Sh NAME .Nm profil .Nd control process profiling .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In unistd.h .Ft int .Fn profil "char *samples" "size_t size" "u_long offset" "u_int scale" .Sh DESCRIPTION .Pp .Fd -- This function is now deprecated. It will always return EINVAL. -- .Pp The intended replacements are the user-level developer tools, like CHUD and dtrace. .Pp ------ .Pp The .Fn profil function enables or disables program counter profiling of the current process. If profiling is enabled, then at every clock tick, the kernel updates an appropriate count in the .Fa samples buffer. .Pp The buffer .Fa samples contains .Fa 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 clock tick occurred while profiling was enabled. For a given program counter address, the number of the corresponding bin is given by the relation: .Bd -literal -offset indent [(pc - offset) / 2] * scale / 65536 .Ed .Pp The .Fa offset parameter is the lowest address at which the kernel takes program counter samples. The .Fa scale parameter ranges from 1 to 65536 and can be used to change the span of the bins. A scale of 65536 maps each bin to 2 bytes of address range; a scale of 32768 gives 4 bytes, 16384 gives 8 bytes and so on. Intermediate values provide approximate intermediate ranges. A .Fa scale value of 0 disables profiling. .Sh RETURN VALUES If the .Fa scale value is nonzero and the buffer .Fa samples contains an illegal address, .Fn profil returns \-1, profiling is terminated and .Va errno is set appropriately. Otherwise .Fn profil returns 0. .Sh FILES .Bl -tag -width /usr/lib/gcrt0.o -compact .It Pa /usr/lib/gcrt0.o profiling C run-time startup file .It Pa gmon.out conventional name for profiling output file .El .Sh ERRORS The following error may be reported: .Bl -tag -width Er .It Bq Er EFAULT The buffer .Fa samples contains an invalid address. .El .Sh SEE ALSO .Xr gprof 1 .Sh HISTORY The .Fn profil function appeared in .At v7 . .Sh BUGS This routine should be named .Fn profile . .Pp The .Fa samples argument should really be a vector of type .Fa "unsigned short" . .Pp The format of the gmon.out file is undocumented.