Mispredicted Path Cache Effects

  • Jonathan Combs
  • Candice Bechem Combs
  • John Paul Shen
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1685)


As superscalar pipelines become wider and deeper, the percentage of dynamic instructions fetched into the machine from the mispredicted path significantly increases. This paper discusses how a new cycle-accurate performance simulator is used to accurately measure mispredicted path effects on the cache hierarchy. Previously published results based on less accurate tools indicated that mispredicted path instructions have the serendipitous positive effect of doing memory prefetching. Our results show that while such prefetching does occur for some benchmarks, it does not occur consistently for all benchmarks. Furthermore the IPC impact varies widely among the benchmarks. SPECint95 benchmarks show IPC changes ranging from -8% to +12%.


Memory Latency Instruction Cache Speculative Execution Branch Prediction Cache Hierarchy 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Jonathan Combs
    • 1
  • Candice Bechem Combs
    • 1
  • John Paul Shen
    • 1
  1. 1.Carnegie Mellon Microarchitecture Research Team (CMuART) Department of Electrical and Computer EngineeringCarnegie Mellon UniversityPittsburghUSA

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