xii Contents 5.10 Summary of Results for Optimizing Combining Code 547 5.11 Some Limiting Factors 548 5.11.1 Register Spilling 548 5.11.2 Branch Prediction and.Misprediction Penalties549 5.12 Understanding Memory Performance 553 5.12.1 Load Performance 554ti 5.12.2 Store Performance 555 r 5.13 Life in the Real World:Performance'Improvement Techniques561 5.14 Identifying and Eliminating Performance Bottlenecks 562 5.14.1 Program Profiling 562 5.14.2 Using a Profiler to Guide Optimization 565 5.15 Summary 568 Bibliographic Notes 569 Homework Problems 570 Solutions to Practice Problems 573 6 The Memory Hierarchy 579 6.1 Storage Technologies 581 6.1.1 Random Access Memory 581 6.1.2 Disk Storage 589 6.1.3 Solid State Disks 600 6.1.4 Storage Technology Trends 602 6.2 Locality 604 6.2.1 Locality of References to Program Data 606 62.Locality of Instruction Fetche 6.2.3 Summary of Locality 608 6.3 The Memory Hierarchy 609 6.3.1 Caching in the Memory Hierarchy 610 6.3.2 Summary of Memory Hierarchy Concepts 614 6.4 Cache Memories 614 6.4.1 Generic Cache Memory Organization 615 6.4.2 Direct-Mapped Caches 617 6.4.3 Set Associative Caches 624 6.4.4 Fully Associative Caches 626 6.4.5 Issues with Writes 630 6.4.6 Anatomy of a Real Cache Hierarchy 631 6.4.7 Performance Impact of Cache Parameters 631 6.5 Writing Cache-Friendly Code 633 6.6 Putting It Together:The Impact of Caches on Program Performance 639Xii Contents 5.10 Summary of Results for Optimizing Combining Code 547 5.11 Some Limiting Factors 548 5.11.1 Register Spilling 548 5.11.2 Branch Prediction and·Mispredictipn Penalties ·'549 5.12 Understanding Memory Performance 553 ,... •L 5.12.1 Load Performance 554'ri 1 d" 5.12.2 Store Performance 555 5.13 Life in the Real World: Performance"Improvement Techniques • 561 5.14 Identifying and Eliminating Performance Bottlenecks 562 5.14.1 Program Profiling 562 5.14.2 Using a Profiler to Guide Optimization 565 • 5.15 Summary 568 Bibliographic Notes 569 " Homework Problems 570 Solutions to Practice Problems 573 6 The Memory Hierarchy 579 6.1 Storage Technologies 581 6.1.1 Random Access Memory 581 6.1.2 Disk Storage 589 6.1.3 Solid State Disks 600 6.1.4 Storage Technology Trends 602 6.2 Locality 604 6.2.1 Locality of References to Program Data 606 6.2.2 Locality of Instruc,tion Fetche'l , 601 6.2.3 Summary of Locality 608 "' 6.3 The Memory Hierarchy 609 6.3.1 Caching in the Memory Hierarchy 610 6.3.2 Summary of Memory Hierarchy Concepts 614 6.4 Cache Memories 614 6.4.1 Generic Cache Memory Organization '615 6.4.2 Direct-Mapped Caches 617 " 6.4.3 Set Associative Cadres 624 " 6.4.4 Fully Associative Caches 626 6.4.5 Issues with Writes 630 6.4.6 Anatomy of a Real Cache Hierarchy 631 6.4.7 Performance Impact of Cache Parameters 631 6.5 Writing Cache-Friendly Code 633 6.6 Putting It Together: The Impact of Caches on Program Performance 639