Activating LTTng traces

Advanced usage

When you want to collect traces, you must :

• create a session
• enable the event you want to collect
• start trace collection

Creating a session

To create a session, use the command

lttng create

It will create a session in the folder ${HOME}/lttng-traces/ within a sub-folder named auto followed by the current date.

You can specify the session name with

lttng create mysession

The folder name will then be mysession followed by the current date.

Enabling events

You can enable a lot of events when using LTTng, from the user and the kernel space, from several namespaces, and even filter the events you want to collect.

To collect MAUVE traces, use

lttng enable-event -u mauve:*

It enable user event (-u) with name mauve:*, meaning all the events in namespace mauve.

Starting and stopping trace collection

To start trace collection, use

lttng start

To stop trace collection, use

lttng stop

You can use these commands at any time while your program is running.

Closing the session

In order to use your session traces, you must close the session

lttng destroy