xref: /freebsd/lib/libc/gmon/moncontrol.3 (revision 40a8ac8f62b535d30349faf28cf47106b7041b83)
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28.\"	@(#)moncontrol.3	8.1 (Berkeley) 6/4/93
29.\" $FreeBSD$
30.\"
31.Dd June 14, 2004
32.Dt MONCONTROL 3
33.Os
34.Sh NAME
35.Nm moncontrol ,
36.Nm monstartup
37.Nd control execution profile
38.Sh LIBRARY
39.Lb libc
40.Sh SYNOPSIS
41.In sys/types.h
42.In sys/gmon.h
43.Ft void
44.Fn moncontrol "int mode"
45.Ft void
46.Fn monstartup "u_long lowpc" "u_long highpc"
47.Sh DESCRIPTION
48An executable program compiled using the
49.Fl pg
50option to
51.Xr cc 1
52automatically includes calls to collect statistics for the
53.Xr gprof 1
54call-graph execution profiler.
55In typical operation, profiling begins at program startup
56and ends when the program calls exit.
57When the program exits, the profiling data are written to the file
58.Ar progname Ns Pa .gmon ,
59where progname is the name of the program, then
60.Xr gprof 1
61can be used to examine the results.
62.Pp
63The
64.Fn moncontrol
65function
66selectively controls profiling within a program.
67When the program starts, profiling begins.
68To stop the collection of histogram ticks and call counts use
69.Fn moncontrol 0 ;
70to resume the collection of histogram ticks and call counts use
71.Fn moncontrol 1 .
72This feature allows the cost of particular operations to be measured.
73Note that an output file will be produced on program exit
74regardless of the state of
75.Fn moncontrol .
76.Pp
77Programs that are not loaded with
78.Fl pg
79may selectively collect profiling statistics by calling
80.Fn monstartup
81with the range of addresses to be profiled.
82The
83.Fa lowpc
84and
85.Fa highpc
86arguments
87specify the address range that is to be sampled;
88the lowest address sampled is that of
89.Fa lowpc
90and the highest is just below
91.Fa highpc .
92Only functions in that range that have been compiled with the
93.Fl pg
94option to
95.Xr cc 1
96will appear in the call graph part of the output;
97however, all functions in that address range will
98have their execution time measured.
99Profiling begins on return from
100.Fn monstartup .
101.Sh ENVIRONMENT
102The following environment variables affect the execution of
103.Nm :
104.Bl -tag -width ".Ev PROFIL_USE_PID"
105.It PROFIL_USE_PID
106If set, the pid of the process is inserted into the filename.
107.El
108.Sh FILES
109.Bl -tag -width progname.gmon -compact
110.It Pa progname.gmon
111execution data file
112.El
113.Sh SEE ALSO
114.Xr cc 1 ,
115.Xr gprof 1 ,
116.Xr profil 2 ,
117.Xr clocks 7
118