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KTRACE(1)              DragonFly General Commands Manual             KTRACE(1)


ktrace - enable kernel process tracing


ktrace [-aCcdi] [-f trfile] [-g pgrp | -p pid] [-t trstr] ktrace [-adi] [-f trfile] [-t trstr] command


The ktrace utility enables kernel trace logging for the specified processes. By default, kernel trace data is logged to the file ktrace.out, this may be overridden by the -f option. The kernel operations that are traced include system calls, namei translations, signal processing, and I/O. Once tracing is enabled on a process, trace data will be logged until either the process exits or the trace point is cleared. A traced process can generate enormous amounts of log data quickly; It is strongly suggested that users memorize how to disable tracing before attempting to trace a process. The following command is sufficient to disable tracing on all user owned processes, and, if executed by root, all processes: $ ktrace -C The trace file is not human readable; use kdump(1) to decode it. The options are as follows: -a Append to the trace file instead of recreating it. -C Disable tracing on all user owned processes, and, if executed by root, all processes in the system. -c Clear the trace points associated with the specified file or processes. -d Descendants; perform the operation for all current children of the designated processes. -f trfile Log trace records to trfile instead of ktrace.out. -g pgid Enable (disable) tracing on all processes in the process group (only one -g flag is permitted). -i Inherit; pass the trace flags to all future children of the designated processes. -p pid Enable (disable) tracing on the indicated process id (only one -p flag is permitted). -t trstr The string argument represents the kernel trace points, one per letter. The following table equates the letters with the tracepoints: c trace system calls n trace namei translations i trace I/O s trace signal processing u userland traces w context switches y trace sysctl(3) requests * trace the default set of trace points - c, n, i, s, u, y command Execute command with the specified trace flags. The -p, -g, and command options are mutually exclusive.


ktrace.out default ktrace dump file


# trace all kernel operations of process id 34 $ ktrace -p 34 # trace all kernel operations of processes in process group 15 and # pass the trace flags to all current and future children $ ktrace -idg 15 # disable all tracing of process 65 $ ktrace -cp 65 # disable tracing signals on process 70 and all current children $ ktrace -t s -cdp 70 # enable tracing of I/O on process 67 $ ktrace -ti -p 67 # run the command "w", tracing only system calls $ ktrace -tc w # disable all tracing to the file "tracedata" $ ktrace -c -f tracedata # disable tracing of all processes owned by the user $ ktrace -C


kdump(1), ktrace(2), utrace(2)


The ktrace command appeared in 4.4BSD.


Only works if trfile is a regular file. DragonFly 6.5-DEVELOPMENT April 4, 2023 DragonFly 6.5-DEVELOPMENT

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