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The Global Tracking Unit of the ALICE Transition Radiation Detector is a high-speed, low-latency trigger processor installed at the ALICE experiment at the Large Hadron Collider. Based on the analysis of up to 20,000 parametrized particle track segments per event, a trigger decision is formed within approx. 2 μs. Furthermore, the system is designed to significantly improve the overall detector performance by providing a complex and robust multi-event buffering scheme. Data from the detector arrives at an aggregate net bandwidth of 2.16Tbit/s via 1080 optical links and is processed massively in parallel by 109 FPGA-based units organized in a 3-stage hierarchical structure. The embedded PowerPC cores are employed not only to build a monitoring and control system that can be interfaced by the experiment control. They are also used to realize a real-time hardware/software co-design, able to characterize the trigger performance, supervise the operation and intervene in cases of system errors.