US Patent 9058415 Counting events using hardware performance counters and annotated instructions

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for receiving a plurality of instructions, where the plurality of instructions comprise one or more first instructions from an application and one or more second instructions from a profiler that instruments the application with the one or more second instructions; identifying, for each of one or more instructions in the plurality of instructions, a respective prefix from one or more prefixes based on a category of the respective instruction; annotating each of the one or more instructions with the respective prefix; and for at least one of one or more hardware performance counters, configuring the respective hardware performance counter to count each instruction in the plurality of instructions that is annotated by one or more of the respective prefixes.