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33 .Nd display kernel trace data
44 command displays the kernel trace files produced with
46 in human readable format.
49 in the current directory is displayed.
51 The options are as follows:
54 Display the ABI of the traced process.
56 Display the CPU number with each trace entry.
58 Display all numbers in decimal.
60 Display elapsed timestamps (time since beginning of trace).
62 Display the specified file instead of
65 List the thread ID (tid) of the thread with each trace record, if available.
66 If no thread ID is available, 0 will be printed.
68 Loop reading the trace file, once the end-of-file is reached, waiting for
76 Suppress ad hoc translations.
79 tries to decode many system calls into a more human readable format.
82 values are replaced with the macro name and
84 values are replaced with the
87 Suppressing this feature yields a more consistent output format and is
88 easily amenable to further processing.
90 Display only trace events that correspond to the process or thread
92 This may be useful when there are multiple processes or threads recorded in the
95 Display relative timestamps (time since previous entry).
97 When decoding STRU records, display structure members such as UIDs,
98 GIDs, dates etc. symbolically instead of numerically.
100 Display system call numbers.
102 Suppress display of I/O data.
104 Display absolute timestamps for each entry (seconds since epoch).
114 is line oriented with several fields.
115 The example below shows a section of a kdump generated by the following
117 .Bd -literal -offset indent
118 ?> ktrace echo "ktrace"
122 85045 echo CALL writev(0x1,0x804b030,0x2)
123 85045 echo GIO fd 1 wrote 7 bytes
126 85045 echo RET writev 7
129 The first field is the PID of the process being traced.
130 The second field is the name of the program being traced.
131 The third field is the operation that the kernel performed
132 on behalf of the process.
133 If thread IDs are being printed, then an additional thread ID column will be
134 added to the output between the PID field and program name field.
136 In the first line above, the kernel executes the
138 system call on behalf of the process so this is a
141 The fourth field shows the system call that was executed,
142 including its arguments.
145 system call takes a file descriptor, in this case 1, or standard
146 output, then a pointer to the iovector to write, and the number of
147 iovectors that are to be written.
148 In the second line we see the operation was
150 for general I/O, and that file descriptor 1 had
151 seven bytes written to it.
152 This is followed by the seven bytes that were written, the string
154 with a carriage return and line feed.
157 operation, showing a return from the kernel, what system call we are
158 returning from, and the return value that the process received.
159 Seven bytes were written by the
161 system call, so 7 is the return value.
163 The possible operations are:
164 .Bl -column -offset indent ".Li CALL" ".No data from user process"
165 .It Sy Name Ta Sy Operation Ta Sy Fourth field
166 .It Li CALL Ta enter syscall Ta syscall name and arguments
167 .It Li RET Ta return from syscall Ta syscall name and return value
168 .It Li NAMI Ta file name lookup Ta path to file
169 .It Li GIO Ta general I/O Ta fd, read/write, number of bytes
170 .It Li PSIG Ta signal Ta signal name, handler, mask, code
171 .It Li CSW Ta context switch Ta stop/resume user/kernel wmesg
172 .It Li USER Ta data from user process Ta the data
173 .It Li STRU Ta various syscalls Ta structure
174 .It Li SCTL Ta Xr sysctl 3 requests Ta MIB name
175 .It Li PFLT Ta enter page fault Ta fault address and type
176 .It Li PRET Ta return from page fault Ta fault result