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Diffstat (limited to 'doc/developer/tracing.rst')
| -rw-r--r-- | doc/developer/tracing.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/doc/developer/tracing.rst b/doc/developer/tracing.rst index d54f6c7aaa..c194ae1270 100644 --- a/doc/developer/tracing.rst +++ b/doc/developer/tracing.rst @@ -308,6 +308,31 @@ Limitations Tracers do not like ``fork()`` or ``dlopen()``. LTTng has some workarounds for this involving interceptor libraries using ``LD_PRELOAD``. +If you're running FRR in a typical daemonizing way (``-d`` to the daemons) +you'll need to run the daemons like so: + +.. code-block:: shell + + LD_PRELOAD=liblttng-ust-fork.so <daemon> + + +If you're using systemd this you can accomplish this for all daemons by +modifying ``frr.service`` like so: + +.. code-block:: diff + + --- a/frr.service + +++ b/frr.service + @@ -7,6 +7,7 @@ Before=network.target + OnFailure=heartbeat-failed@%n.service + + [Service] + +Environment="LD_PRELOAD=liblttng-ust-fork.so" + Nice=-5 + Type=forking + NotifyAccess=all + + USDT tracepoints are relatively high overhead and probably shouldn't be used for "flight recorder" functionality, i.e. enabling and passively recording all events for monitoring purposes. It's generally okay to use LTTng like this, |