Understanding the Effects of Wrong-Path Memory References on Processor Performance

Overview

High-performance out-of-order processors spend a significant portion of their execution time on the incorrect program path even though they employ aggressive branch pre-diction algorithms. Although memory references generated on the wrong path do not change the architectural state of the processor, they can affect the arrangement of data in the memory hierarchy. This paper examines the effects of wrong-path memory references on processor performance. It is shown that these references significantly affect the IPC (Instructions Per Cycle) performance of a processor.