Currently, only PHP APM agent(version 1.0.1 or higher) supports the trace.
By default, trace is disabled in PHP configuration. You can enable trace in the atatus.ini. You can find the path of the "atatus.ini" as follows
In a command line, run the following command.php -i | grep atatus.ini
In the "atatus.ini", enable the trace as follows
atatus.trace.enabled = true
You have to restart your web server. After few requests to the server, you will start seeing the traces.