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25 .\" $FreeBSD: src/share/man/man9/ktr.9,v 1.8 2005/03/08 01:37:36 hmp Exp $
32 .Nm KTR_INFO_MASTER_EXTERN ,
35 .Nd kernel tracing facility
38 .Vt "extern int ktr_entries" ;
39 .Vt "extern int ktr_verbose" ;
40 .Vt "extern struct ktr_entry *ktr_buf[MAXCPU]" ;
41 .Fn KTR_INFO_MASTER "master"
42 .Fn KTR_INFO_MASTER_EXTERN "master"
43 .Fn KTR_INFO "compile" "master" "name" "maskbit" "format" "datasize"
44 .Fn KTR_LOG "info" "arg ..."
48 facility provides a circular buffer of events that can be logged in a
51 These events can then be dumped with
58 declares a new master variable
59 .Dv ktr Ns _ Ns Fa master Ns _ Ns Dv enable
60 that is used to turn on and off event logging.
61 .Fn KTR_INFO_MASTER_EXTERN
62 is a convenience macro for declaring a master variable
67 macro registers a new event
69 that will be controlled by the
72 Code for logging this event will be compiled in when
77 argument is a limited (i.e.\& only integral types, no formatting)
79 style format string used to build the text of the event log message while
81 specifies the size of the data to be logged, either the total size of the
82 arguments required by the
85 For logging a fixed string with
91 is a bit number that determines which of the corresponding
92 .Va debug.ktr.*_enable
93 sysctl's bits will enable logging of this event.
95 Kernel events are logged via the
100 parameter is an identifier of the format
101 .Fa master Ns _ Ns Fa name .
103 accepts zero or more additional
105 arguments as required by the
107 string passed to the associated
113 variable contains the number of entries in the
116 These variables are mostly useful for post-mortem crash dump tools to locate
117 the base of the circular trace buffer and its length.
121 variable stores the verbose flag that controls whether events are logged to
122 the console in addition to the event buffer.
124 This example demonstrates a simple usage of the KTR facility:
126 .Bd -literal -compact
131 #if !defined(KTR_FOO)
132 #define KTR_FOO KTR_ALL
134 KTR_INFO_MASTER(foo);
135 KTR_INFO(KTR_FOO, foo, func1, 0, "func1()", 0);
136 KTR_INFO(KTR_FOO, foo, func2, 1, "func2(%d)", sizeof(int));
150 KTR_LOG(foo_func2, arg);
163 kernel tracing facility first appeared in
165 and was imported into
169 It was completely rewritten by Matthew Dillon in