Bring in the ktrdump(8) utility from FreeBSD.
[dragonfly.git] / share / man / man9 / ktr.9
CommitLineData
81540c2d
EN
1.\" Copyright (c) 2001 John H. Baldwin <jhb@FreeBSD.org>
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\" notice, this list of conditions and the following disclaimer in the
11.\" documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
25.\" $FreeBSD: src/share/man/man9/ktr.9,v 1.7 2003/09/08 19:57:21 ru Exp $
bd02a712 26.\" $DragonFly: src/share/man/man9/ktr.9,v 1.4 2005/03/08 01:19:10 hmp Exp $
81540c2d
EN
27.\"
28.Dd February 15, 2001
29.Dt KTR 9
30.Os
31.Sh NAME
32.Nm CTR0 , CTR1 , CTR2 , CTR3 , CTR4 , CTR5 , CTR6
33.Nd kernel tracing facility
34.Sh SYNOPSIS
35.In sys/param.h
36.In sys/ktr.h
37.Vt "extern int ktr_cpumask" ;
38.Vt "extern int ktr_entries" ;
39.Vt "extern int ktr_extend" ;
40.Vt "extern int ktr_mask" ;
41.Vt "extern int ktr_verbose" ;
42.Vt "extern struct ktr_entry ktr_buf[]" ;
43.Ft void
44.Fn CTR0 "u_int mask" "char *format"
45.Ft void
46.Fn CTR1 "u_int mask" "char *format" "arg1"
47.Ft void
48.Fn CTR2 "u_int mask" "char *format" "arg1" "arg2"
49.Ft void
50.Fn CTR3 "u_int mask" "char *format" "arg1" "arg2" "arg3"
51.Ft void
52.Fn CTR4 "u_int mask" "char *format" "arg1" "arg2" "arg3" "arg4"
53.Ft void
54.Fn CTR5 "u_int mask" "char *format" "arg1" "arg2" "arg3" "arg4" "arg5"
55.Ft void
56.Fn CTR6 "u_int mask" "char *format" "arg1" "arg2" "arg3" "arg4" "arg5" "arg6"
57.Sh DESCRIPTION
58KTR provides a circular buffer of events that can be logged in a
59.Xr printf 9
60style
61fashion.
62These events can then be dumped either via
63.Xr ddb 4
64or
65.Xr gdb 1 .
66.Pp
67Events are created and logged in the kernel via the
68.Dv CTR Ns Ar x
69macros.
70The first parameter is a mask of event types
71.Pq Dv KTR_*
72defined in
e5ab4b11 73.Aq Pa sys/ktr.h .
81540c2d
EN
74The event will be logged only if any of the event types specified in
75.Fa mask
76are enabled in the global event mask stored in
77.Va ktr_mask .
78The
79.Fa format
80argument is a
81.Xr printf 9
82style format string used to build the text of the event log message.
83Following the
84.Fa format
85string are zero to five arguments referenced by
86.Fa format .
87Note that the different macros differ only in the number of arguments each
88one takes, as indicated by its name.
89Each event is logged with a timestamp in addition to the log message.
90.Pp
91The
92.Va ktr_entries
93variable contains the number of entries in the
94.Va ktr_buf
95array.
96These variables are mostly useful for post-mortem crash dump tools to locate
97the base of the circular trace buffer and its length.
98.Pp
99The
100.Va ktr_mask
101variable contains the run time mask of events to log.
102.Pp
103The CPU event mask is stored in the
104.Va ktr_cpumask
105variable.
106.Pp
107The
108.Va ktr_verbose
109variable stores the verbose flag that controls whether events are logged to
110the console in addition to the event buffer.
111.Sh EXAMPLES
112This example demonstrates the use of tracepoints at the
113.Dv KTR_PROC
114logging level.
bd02a712 115.Bd -literal -compact
81540c2d
EN
116void
117mi_switch()
118{
119 ...
120 /*
121 * Pick a new current process and record its start time.
122 */
123 ...
124 CTR3(KTR_PROC, "mi_switch: old proc %p (pid %d, %s)", p, p->p_pid,
125 p->p_comm);
126 ...
127 cpu_switch();
128 ...
129 CTR3(KTR_PROC, "mi_switch: new proc %p (pid %d, %s)", p, p->p_pid,
130 p->p_comm);
131 ...
132}
133.Ed
134.Sh SEE ALSO
135.Xr ktr 4
136.Sh HISTORY
137The KTR kernel tracing facility first appeared in
138.Bsx 3.0
139and was imported into
140.Fx 5.0
141and
142.Dx 1.1 .