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28 .\" @(#)ktrace.1 8.1 (Berkeley) 6/6/93
29 .\" $FreeBSD: src/usr.bin/ktrace/ktrace.1,v 1.8.2.8 2002/06/21 15:27:30 charnier Exp $
36 .Nd enable kernel process tracing
41 .Op Fl g Ar pgrp | Fl p Ar pid
51 utility enables kernel trace logging for the specified processes.
52 By default, kernel trace data is logged to the file
54 this may be overridden by the
57 The kernel operations that are traced include system calls, namei
58 translations, signal processing, and I/O.
60 Once tracing is enabled on a process, trace data will be logged until
61 either the process exits or the trace point is cleared.
62 A traced process can generate enormous amounts of log data quickly;
63 It is strongly suggested that users memorize how to disable tracing before
64 attempting to trace a process.
65 The following command is sufficient to disable tracing on all user owned
66 processes, and, if executed by root, all processes:
70 The trace file is not human readable; use
74 The options are as follows:
75 .Bl -tag -width indent
77 Append to the trace file instead of recreating it.
79 Disable tracing on all user owned processes, and, if executed by root, all
80 processes in the system.
82 Clear the trace points associated with the specified file or processes.
84 Descendants; perform the operation for all current children of the
92 Enable (disable) tracing on all processes in the process group (only one
96 Inherit; pass the trace flags to all future children of the designated
99 Enable (disable) tracing on the indicated process id (only one
103 The string argument represents the kernel trace points, one per letter.
104 The following table equates the letters with the tracepoints:
106 .Bl -tag -width flag -compact
110 trace namei translations
114 trace signal processing
120 trace the default set of trace points -
121 .Cm c , n , i , s , u
126 with the specified trace flags.
134 options are mutually exclusive.
136 .Bl -tag -width ktrace.out -compact
138 default ktrace dump file
141 # trace all kernel operations of process id 34
144 # trace all kernel operations of processes in process group 15 and
145 # pass the trace flags to all current and future children
148 # disable all tracing of process 65
151 # disable tracing signals on process 70 and all current children
152 .Dl $ ktrace -t s -cdp 70
154 # enable tracing of I/O
156 .Dl $ ktrace -ti -p 67
158 # run the command "w", tracing only system calls
161 # disable all tracing to the file "tracedata"
162 .Dl $ ktrace -c -f tracedata
164 # disable tracing of all processes owned by the user