System Introspection for System Analysis on Mobile Devices

When a client requests a new logging cycle, the client is added to the locallist and a new logging cycle is created. Components selected by the client areadded to the list of the logging cycle. When the cycle is successfully createdit gets started by the logging dispatcher. If the client sends a stop command<strong>for</strong> a logging cycle, the logging dispatcher checks the list and interrupts thecorresponding cycle. If a client got disconnected while an logging cycle isactive, the logging dispatcher also interrupts the corresponding cycle (Figure5.9).(a) Execute a logging cycle(b) Interrupting a logging cycleFigure 5.9: Logging Dispatcher starting and stopping Logging Cycles- Diagram a shows the process of creating a new LoggingCycle by adding selected components and startingit. Diagram b describes how an active Logging Cycle isinterrupted via command of the client or when the clientis disconnected.Logging Cycle - Writing Logging Output on DemandLogging cycles are designed to create logging files from the components of therobot. A logging cycle is a thread collecting data of multiple components witha frequency configured in the configuration file. Each logging cycle is createdas thread which allows that multiple logging cycles are executed in parallel.The client can request available components to be logged from the probe.Figure 5.10: A Logging Cycle creating corresponding files - Eachreading cycle opens a new element with the current systemtimestamp. The data of each selected componentis read via the Component Holder. This process runs ina loop until it is interrupted by the Logging Dispatcher.If the Logging Cycle gets interrupted, the created documentis written to a file on the probes file system.29