xref: /freebsd/lib/libc/gmon/moncontrol.3 (revision 8f76bb7dad48538c6832c2fb466a433d2a3f8cd5)
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28.\"	@(#)moncontrol.3	8.1 (Berkeley) 6/4/93
29.\"
30.Dd June 14, 2004
31.Dt MONCONTROL 3
32.Os
33.Sh NAME
34.Nm moncontrol ,
35.Nm monstartup
36.Nd control execution profile
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In sys/types.h
41.In sys/gmon.h
42.Ft void
43.Fn moncontrol "int mode"
44.Ft void
45.Fn monstartup "u_long lowpc" "u_long highpc"
46.Sh DESCRIPTION
47An executable program compiled using the
48.Fl pg
49option to
50.Xr cc 1
51automatically includes calls to collect statistics for the
52.Xr gprof 1
53call-graph execution profiler.
54In typical operation, profiling begins at program startup
55and ends when the program calls exit.
56When the program exits, the profiling data are written to the file
57.Ar progname Ns Pa .gmon ,
58where progname is the name of the program, then
59.Xr gprof 1
60can be used to examine the results.
61.Pp
62The
63.Fn moncontrol
64function
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.
81The
82.Fa lowpc
83and
84.Fa highpc
85arguments
86specify the address range that is to be sampled;
87the lowest address sampled is that of
88.Fa lowpc
89and the highest is just below
90.Fa highpc .
91Only functions in that range that have been compiled with the
92.Fl pg
93option to
94.Xr cc 1
95will appear in the call graph part of the output;
96however, all functions in that address range will
97have their execution time measured.
98Profiling begins on return from
99.Fn monstartup .
100.Sh ENVIRONMENT
101The following environment variables affect the execution of
102.Nm :
103.Bl -tag -width ".Ev PROFIL_USE_PID"
104.It PROFIL_USE_PID
105If set, the pid of the process is inserted into the filename.
106.El
107.Sh FILES
108.Bl -tag -width progname.gmon -compact
109.It Pa progname.gmon
110execution data file
111.El
112.Sh SEE ALSO
113.Xr cc 1 ,
114.Xr gprof 1 ,
115.Xr profil 2 ,
116.Xr clocks 7
117