xref: /netbsd/lib/libc/gmon/moncontrol.3 (revision bf9ec67e)
1.\"	$NetBSD: moncontrol.3,v 1.7 2001/09/16 02:29:00 wiz Exp $
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34.\"	@(#)moncontrol.3	8.1 (Berkeley) 6/4/93
35.\"
36.Dd June 4, 1993
37.Dt MONCONTROL 3
38.Os
39.Sh NAME
40.Nm moncontrol ,
41.Nm monstartup
42.Nd control execution profile
43.Sh LIBRARY
44.Lb libc
45.Sh SYNOPSIS
46.Fn moncontrol "int mode"
47.Fn monstartup "u_long *lowpc" "u_long *highpc"
48.Sh DESCRIPTION
49An executable program compiled using the
50.Fl pg
51option to
52.Xr cc 1
53automatically includes calls to collect statistics for the
54.Xr gprof 1
55call-graph execution profiler.
56In typical operation, profiling begins at program startup
57and ends when the program calls exit.
58When the program exits, the profiling data are written to the file
59.Em gmon.out ,
60then
61.Xr gprof 1
62can be used to examine the results.
63.Pp
64.Fn moncontrol
65selectively controls profiling within a program.
66When the program starts, profiling begins.
67To stop the collection of histogram ticks and call counts use
68.Fn moncontrol 0 ;
69to resume the collection of histogram ticks and call counts use
70.Fn moncontrol 1 .
71This feature allows the cost of particular operations to be measured.
72Note that an output file will be produced on program exit
73regardless of the state of
74.Fn moncontrol .
75.Pp
76Programs that are not loaded with
77.Fl pg
78may selectively collect profiling statistics by calling
79.Fn monstartup
80with the range of addresses to be profiled.
81.Fa lowpc
82and
83.Fa highpc
84specify the address range that is to be sampled;
85the lowest address sampled is that of
86.Fa lowpc
87and the highest is just below
88.Fa highpc .
89Only functions in that range that have been compiled with the
90.Fl pg
91option to
92.Xr cc 1
93will appear in the call graph part of the output;
94however, all functions in that address range will
95have their execution time measured.
96Profiling begins on return from
97.Fn monstartup .
98.Sh ENVIRONMENT
99.Bl -tag -width "PROFDIR"
100.It Ev PROFDIR
101Directory to place the output file(s) in.  When this is set, instead of
102writing the profiling output to gmon.out, a filename is generated from
103the process id and name of the program.  (e.g. 123.a.out)  If you are
104profiling a program that forks, or 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 -compact
109.It Pa gmon.out	execution data file
110.El
111.Sh SEE ALSO
112.Xr cc 1 ,
113.Xr gprof 1 ,
114.Xr profil 2
115