xref: /netbsd-src/lib/libc/gmon/moncontrol.3 (revision 746b955e9eaab425dcc9432a45f881986b048350)
1.\"	$NetBSD: moncontrol.3,v 1.10 2009/04/11 15:33:27 joerg Exp $
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30.\"	@(#)moncontrol.3	8.1 (Berkeley) 6/4/93
31.\"
32.Dd June 4, 1993
33.Dt MONCONTROL 3
34.Os
35.Sh NAME
36.Nm moncontrol ,
37.Nm monstartup
38.Nd control execution profile
39.Sh LIBRARY
40.Lb libc
41.Sh SYNOPSIS
42.Fn moncontrol "int mode"
43.Fn monstartup "u_long *lowpc" "u_long *highpc"
44.Sh DESCRIPTION
45An executable program compiled using the
46.Fl pg
47option to
48.Xr cc 1
49automatically includes calls to collect statistics for the
50.Xr gprof 1
51call-graph execution profiler.
52In typical operation, profiling begins at program startup
53and ends when the program calls exit.
54When the program exits, the profiling data are written to the file
55.Em gmon.out ,
56then
57.Xr gprof 1
58can be used to examine the results.
59.Pp
60.Fn moncontrol
61selectively controls profiling within a program.
62When the program starts, profiling begins.
63To stop the collection of histogram ticks and call counts use
64.Fn moncontrol 0 ;
65to resume the collection of histogram ticks and call counts use
66.Fn moncontrol 1 .
67This feature allows the cost of particular operations to be measured.
68Note that an output file will be produced on program exit
69regardless of the state of
70.Fn moncontrol .
71.Pp
72Programs that are not loaded with
73.Fl pg
74may selectively collect profiling statistics by calling
75.Fn monstartup
76with the range of addresses to be profiled.
77.Fa lowpc
78and
79.Fa highpc
80specify the address range that is to be sampled;
81the lowest address sampled is that of
82.Fa lowpc
83and the highest is just below
84.Fa highpc .
85Only functions in that range that have been compiled with the
86.Fl pg
87option to
88.Xr cc 1
89will appear in the call graph part of the output;
90however, all functions in that address range will
91have their execution time measured.
92Profiling begins on return from
93.Fn monstartup .
94.Sh ENVIRONMENT
95.Bl -tag -width "PROFDIR"
96.It Ev PROFDIR
97Directory to place the output file(s) in.
98When this is set, instead of writing the profiling output to
99.Pa gmon.out ,
100a filename is generated from the process id and name of the program
101(e.g.,
102.Pa 123.a.out ) .
103If you are profiling a program that forks,
104or otherwise creates multiple copies,
105setting this is the only reasonable way to get all profiling data.
106.El
107.Sh FILES
108.Bl -tag -width ".Pa gmon.out" -compact
109.It Pa gmon.out
110execution data file
111.El
112.Sh SEE ALSO
113.Xr cc 1 ,
114.Xr gprof 1 ,
115.Xr profil 2
116