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28 .\" @(#)kdump.1 8.1 (Berkeley) 6/6/93
36 .Nd display kernel trace data
47 command displays the kernel trace files produced with
49 in human readable format.
52 in the current directory is displayed.
54 The options are as follows:
57 Display all numbers in decimal.
59 Display elapsed timestamps (time since beginning of trace).
61 Display the specified file instead of
64 List the thread ID (tid) of the thread with each trace record, if available.
65 If no thread ID is available, 0 will be printed.
67 Loop reading the trace file, once the end-of-file is reached, waiting for
75 Suppress ad hoc translations.
78 tries to decode many system calls into a more human readable format.
81 values are replaced with the macro name and
83 values are replaced with the
86 Suppressing this feature yields a more consistent output format and is
87 easily amenable to further processing.
89 Display only trace events that correspond to the process or thread
91 This may be useful when there are multiple processes or threads recorded in the
94 Display relative timestamps (time since previous entry).
96 When decoding STRU records, display structure members such as UIDs,
97 GIDs, dates etc. symbolically instead of numerically.
99 Suppress display of I/O data.
101 Display absolute timestamps for each entry (seconds since epoch).
103 Display description of the ABI of traced process.
113 is line oriented with several fields.
114 The example below shows a section of a kdump generated by the following
116 .Bd -literal -offset indent
117 ?> ktrace echo "ktrace"
121 85045 echo CALL writev(0x1,0x804b030,0x2)
122 85045 echo GIO fd 1 wrote 7 bytes
125 85045 echo RET writev 7
128 The first field is the PID of the process being traced.
129 The second field is the name of the program being traced.
130 The third field is the operation that the kernel performed
131 on behalf of the process.
132 If thread IDs are being printed, then an additional thread ID column will be
133 added to the output between the PID field and program name field.
135 In the first line above, the kernel executes the
137 system call on behalf of the process so this is a
140 The fourth field shows the system call that was executed,
141 including its arguments.
144 system call takes a file descriptor, in this case 1, or standard
145 output, then a pointer to the iovector to write, and the number of
146 iovectors that are to be written.
147 In the second line we see the operation was
149 for general I/O, and that file descriptor 1 had
150 seven bytes written to it.
151 This is followed by the seven bytes that were written, the string
153 with a carriage return and line feed.
156 operation, showing a return from the kernel, what system call we are
157 returning from, and the return value that the process received.
158 Seven bytes were written by the
160 system call, so 7 is the return value.
162 The possible operations are:
163 .Bl -column -offset indent ".Li CALL" ".No data from user process"
164 .It Sy Name Ta Sy Operation Ta Sy Fourth field
165 .It Li CALL Ta enter syscall Ta syscall name and arguments
166 .It Li RET Ta return from syscall Ta syscall name and return value
167 .It Li NAMI Ta file name lookup Ta path to file
168 .It Li GIO Ta general I/O Ta fd, read/write, number of bytes
169 .It Li PSIG Ta signal Ta signal name, handler, mask, code
170 .It Li CSW Ta context switch Ta stop/resume user/kernel wmesg
171 .It Li USER Ta data from user process Ta the data
172 .It Li STRU Ta various syscalls Ta structure
173 .It Li SCTL Ta Xr sysctl 3 requests Ta MIB name
174 .It Li PFLT Ta enter page fault Ta fault address and type
175 .It Li PRET Ta return from page fault Ta fault result