The open source software TraceToolkit is part of the OpenStage telephones in this list.
An overview of all used open source software on OpenStage telephones you find in the category page.
The Linux Trace Toolkit (LTT) is a set of tools that is designed to log program execution details from a Linux kernel and then perform various analyses on them, using console-based and graphical tools.
Modified compared to Original
MAX_NB_INTERRUPTS was increased from 64 ->256 in ./Include/EventDB.h
Changed so visualizer doesn't exit on an unknown event in ./LibLTT/EventDB.c