The context-switch overhead inflicted by hardware interrupts (and the enigma of do-nothing loops)

Abstract

The overhead of a context switch is typically associated with multitasking, where several applications share a processor. But even if only one runnable application is present in the system and supposedly runs alone, it is still repeatedly preempted in favor of a different thread of execution, namely, the operating system that services periodic clock interrupts. We employ two complementing methodologies to measure the overhead incurred by such events and obtain contradictory results.