lttngtoptrace(1) Live textual LTTng Trace Viewer


lttngtoptrace [OPTIONS] [EXECUTABLE]


Lttngtoptrace is a live textual LTTng trace viewer, it allows to easily (one command) start a LTTng session and view the live events. The intent is to do something similar to strace but less intrusive and more flexible:

- run a command and see it's kernel trace almost instantly without slowing it
  down too much (buffered at most 1 second) in combination with the trace of
  any other process or the whole system
- follow multiple processes and/or the whole system
- follow the children of all attached processes
- attach to processes by name and/or pid
- actual time taken by the system calls (with reminder of start timestamp)
- sched_switch events to know the context switches that occurred for the
  process we are interested in
- current CPU (to see the migrations)
- highlight the trace of a selection of processes while tracing the whole
  system to easily see the interactions
- arbitrary kprobe additions to see if a process hits a certain place in the

Only a subset of the LTTng events are enabled (the statedump, sched_switch, sched_process_fork and all the system calls).

The events are displayed with additionnal context information than just the raw LTTng trace (such as the current process name/PID/TID, the start/end time of the current system call, the delay since the last displayed event (filtering aware)).


Follow threads associated with selected PIDs
Comma-separated list of PIDs to display (in addition to the eventual executed program)
Comma-separated list of procnames to display (in addition to the eventual executed program)
In textdump mode, display all events but write in bold the processes we are interested in (-f and -p)
kprobes to insert (same format as lttng enable-event, can be repeated)
-o <filename>
In textdump, output the log in <filename>
Program to run and connect the tracer (can be combined with other options to see the trace of other processes)


A working installation of LTTng >= 2.4, the appropriate rights for the user to create a kernel trace and start daemons (sudo is tried in case the user is not root), Babeltrace = 1.2.4, LTTngTop = 0.3


Some highlighting problems with -a


lttngtoptrace is a wrapper on top of LTTngTop released under the GPLv2 license. See the LICENSE file in the source tree for details.

A Web site is available at for more information on Babeltrace and the Common Trace Format. See for more information on the LTTng project.

Mailing list for support and development: <[email protected]>.

You can find us on IRC server (OFTC) in #lttng.


LTTngTop was originally written and is maintained by Julien Desfossez <[email protected]>