A programmer's view of performance monitoring in the PowerPC microprocessor

Performance monitor (PM) support in on-chip PowerPC® microprocessors is used to analyze processor, software, and system attributes for a variety of workloads. The interface to the PowerPC 604® microprocessor, which we abbreviate “604,” has been externalized to end users. We discuss the enhanced PM support available in an upgrade of the 604, the PowerPC 604e™ microprocessor, which we abbreviate “604e.” We discuss the challenges related to the externalization of the PM support as it relates to other PowerPC processors not derived from the 604 and briefly contrast these PMs with other PMs. We also describe an application programming interface (API) to the on-chip PM support, its design methodology, and its usage considerations, intended to meet these challenges.