A method, apparatus, system, and signal-bearing medium that, in an embodiment, start a timer in response to a program encountering a first breakpoint and halt the program at a second breakpoint if the timer exceeds a condition. If the timer does not exceed the condition, the program is resumed. In various embodiments, the condition may be a value retrieved from the program based on a keyword and may further include a threshold. In another embodiment, after the timer exceeds the condition an interrupt is raised and in response the program counter for the program is changed to be a specified statement. In an embodiment, a loop entry breakpoint is set at a loop entry statement in the program, a loop body breakpoint is set at a loop body statement in the program, and a loop exit breakpoint is set at a loop exit statement in the program. A timer is then started for an iteration period in response to the program encountering the loop entry breakpoint. The timer is reset to the iteration period in response to the program encountering the loop body breakpoint. The timer is canceled in response to the program encountering the loop exit breakpoint.