"Trace-based compilation takes a very different approach. We monitor the interpretation of bytecode instruction by the virtual machine and scan for frequently taken backwards branches, which are an indicator for loops in the underlying program. Once we identify such a loop start point, we follow the interpreter as it executes the program and record the sequence of bytecode instructions that get executed along the way. Since we start at a loop header, the interpreter will eventually return to this entry point once it completed an iteration through the loop. The resulting linear sequence of instructions is what we call a trace."
