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28 .\" @(#)ktrace.1 8.1 (Berkeley) 6/6/93
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 Kernel trace data is logged to the file
54 The kernel operations that are traced include system calls, namei
55 translations, signal processing, and
58 Once tracing is enabled on a process, trace data will be logged until
59 either the process exits or the trace point is cleared.
60 A traced process can generate enormous amounts of log data quickly;
61 It is strongly suggested that users memorize how to disable tracing before
62 attempting to trace a process.
63 The following command is sufficient to disable tracing on all user-owned
64 processes, and, if executed by root, all processes:
68 The trace file is not human readable; use
72 The utility may be used only with a kernel that has been built with the
74 option in the kernel configuration file.
77 .Bl -tag -width indent
79 Append to the trace file instead of recreating it.
81 Disable tracing on all user-owned processes, and, if executed by root, all
82 processes in the system.
84 Clear the trace points associated with the specified file or processes.
86 Descendants; perform the operation for all current children of the
94 Enable (disable) tracing on all processes in the process group (only one
98 Inherit; pass the trace flags to all future children of the designated
101 Enable (disable) tracing on the indicated process id (only one
105 The string argument represents the kernel trace points, one per letter.
106 The following table equates the letters with the tracepoints:
108 .Bl -tag -width flag -compact
115 trace namei translations
117 trace capability check failures
119 trace signal processing
121 trace various structures
131 trace the default set of trace points -
132 .Cm c , i , n , p , s , t , u , y
137 with the specified trace flags.
145 options are mutually exclusive.
147 # trace all kernel operations of process id 34
150 # trace all kernel operations of processes in process group 15 and
151 # pass the trace flags to all current and future children
154 # disable all tracing of process 65
157 # disable tracing signals on process 70 and all current children
158 .Dl $ ktrace -t s -cdp 70
163 .Dl $ ktrace -ti -p 67
165 # run the command "w", tracing only system calls
168 # disable all tracing to the file "tracedata"
169 .Dl $ ktrace -c -f tracedata
171 # disable tracing of all user-owned processes