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KDUMP(1) General Commands Manual KDUMP(1)

kdump — display kernel trace data

kdump [-dHlnRTXx] [-f file] [-m maxdata] [-p pid] [-t [cinpstuxX+]]

kdump displays the kernel trace files produced with ktrace(1) in human-readable format. By default, the file ktrace.out in the current directory is displayed, unless overridden by the -f option.

The options are as follows:

Display all numbers in decimal. By default, values are printed out in hexadecimal.
file
Display the specified file instead of ktrace.out.
Display thread identifiers.
Loop reading the trace file, once the end-of-file is reached, waiting for more data.
maxdata
Display at most maxdata bytes when decoding I/O.
Suppress ad hoc translations. Normally kdump tries to decode many system calls into a more human-readable format. For example, ioctl(2) values are replaced with the macro name and errno values are replaced with the strerror(3) string. Suppressing this feature yields a more consistent output format and is easily amenable to further processing.
pid
Show output only for the pid specified.
Display relative timestamps (time since previous entry).
Display absolute timestamps for each entry (seconds since the Epoch).
If both options are specified, display timestamps relative to trace start.
[cinpstuxX+]
Selects which tracepoints to display. See the -t option of ktrace(1) for the definitions of the flags.
Display I/O data with hexadecimal data and printable ASCII characters side by side.
Display I/O data in hexadecimal.

ktrace.out
default ktrace dump file

ktrace(1)

The kdump command appeared in 4.4BSD.

July 18, 2016 OpenBSD-6.1