One embodiment of the present invention provides a system for measuring processor performance during speculative-execution. The system starts by executing instructions in a normal-execution mode. The system then enters a speculative-execution episode wherein instructions are speculatively executed without being committed to the architectural state of the processor. While entering the speculative-execution episode the system enables a speculative execution monitor. The system then uses the speculative execution monitor to monitor instructions during the speculative-execution episode to record data values relating to the speculative-execution episode. Upon returning to normal-execution mode, the system disables the speculative execution monitor. The data values recorded by the speculative execution monitor facilitate measuring processor performance during speculative execution.