After more than two years of development, the Linux trace toolkit next generation (LTTng)
project has released version 2.11.0 of the kernel and user-space tracing
tool. The release covers the LTTng tools, LTTng user-space tracer, and
LTTng kernel modules. It includes a number of new features that are
described in the announcement including session rotation, dynamic user-space tracing,
call-stack capturing for the kernel and user space, improved networking
performance, NUMA awareness for user-space tracing buffer allocation, and
more. “The biggest feature of this release is the long-awaited session
rotation support. Session rotations now allow you to rotate an
ongoing tracing session much in the same way as you would rotate
logs.

The ‘lttng rotate’ command rotates the current trace chunk of
the current tracing session. Once a rotation is completed, LTTng does
not manage the trace chunk archive anymore: you can read it, modify it,
move it, or remove it.

Because a rotation causes the tracing session’s current sub-buffers
to be flushed, trace chunk archives are never redundant, that is, they
do not overlap over time, unlike snapshots.

Once a rotation is complete, offline analyses can be performed on
the resulting trace, much like in ‘normal’ mode. However, the big
advantage is that this can be done without interrupting tracing, and
without being limited to tools which implement the ‘live’ protocol.“

Source: LWN.net – LTTng 2.11.0 “Lafontaine” released