Multi-threaded HENP Event Reconstruction

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Welcome Tutorial How-to guides Principles Reference

JANA Status/Control Monitoring and Debugging GUI

A very basic GUI program is included with JANA2 to help with monitoring and debugging JANA2 applications. The JANA2 process that is to be monitored/debugged can be running on either the local node or a remote node. For this to work, the following criteria must be met:

  1. JANA must have been compiled with ZEROMQ support. (This relies on cmake find_package(ZEROMQ) successfully finding it when camke is run.)

  2. The python3 environment must me present and have zmq installed. (e.g. pip3 install zmq)

  3. The JANA process must have been started with the janacontrol plugin. This should generally be added to the end of the plugin list like this:

    jana -Pplugins=JTest,janacontrol

By default, it will try to attach to port 11238 on the localhost. It does not matter whether the JANA process is already running or not. It will automatically connect when it starts and reconnect if the process is restarted.

The following command line options are available:

-h, --help     Print this Usage statement and exit
--host HOST    Set the host of the JANA process to monitor
--port PORT    Set the port on the host to connect to

n.b. To set the port used by the remote JANA process set the jana:zmq_port configuration parameter when that process is started.


The GUI can be used to step through events in the JANA process and view the objects, with some limitations. If the data object inherits from JObject then it will display fields obtained from the subclass’ Summarize method. (See JObject::Summarize for details). If the data object inherits from ROOT’s TObject then an attempt is made to extract the data members via the dictionary. Note that this relies on the dictionary being available in the plugin and there are limitations to the complexity of the objects that can be displayed.

When the debugger window is opened (by pushing the “Debugger” button on the main GUI window), it will stall event processing so that single events can be examined and stepped through. To stall processing on the very first event, the JANA process should have the jana:debug_mode config. parameter set to a non-zero value when it is started. e.g.

jana -Pplugins=myplugin1,myplugin2,janacontrol -Pjana:debug_mode=1 file1.dat

Once an event is loaded, click on a factory to display a list of objects it created for this event (displayed as the object’s hexadecimal address). Click on an object to display its content summary (if they are accessible). n.b. clicking on a factory will NOT cause the factory algorithm to activate and create objects for the event. It will only display objects created by other plugins having activated the algorithm.