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Haskell Optimization Handbook
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Haskell Optimization Handbook

Table of Contents

  • 1. Preliminaries
    • 1.1. How to Use This Book
    • 1.2. Triage
    • 1.3. The Checklist
    • 1.4. The Programs of Consistent Lethargy
    • 1.5. Philosophies of Optimization
    • 1.6. The Golden Rules of Performance-Oriented Haskell
    • 1.7. Setting up a Reproducible Test Environment
    • 1.8. How To Debug
  • 2. Measurement, Profiling, and Observation
    • 2.1. Binary Profiling and Probing
    • 2.2. Thread Level Profiling
    • 2.3. Cmm Probes and Profiling
    • 2.4. Stg and RTS Probes and Profiling
    • 2.5. Core Probes and Profiling
    • 2.6. Haskell Level Probing and Profiling
  • 3. Optimizations
    • 3.1. GHC Flags
    • 3.2. GHC Optimizations
    • 3.3. Library Based Changes
    • 3.4. Library Agnostic Changes
  • 4. Case Studies
    • 4.1. Impact of Seq Removal on SBV’s Internal Cache
    • 4.2. SBV and the Bizarre GHC Regression
    • 4.3. Klister: A First Pass Performance Engineering
    • 4.4. Rearchitecting with Data-Oriented Design
  • Glossary
Haskell Optimization Handbook
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3. Optimizations

3. Optimizations¶

  • 3.1. GHC Flags
    • 3.1.1. GHC Flags
  • 3.2. GHC Optimizations
    • 3.2.1. Defunctionalization
    • 3.2.2. The Static Arguments Transformation
    • 3.2.3. Lambda Lifting
      • 3.2.3.1. A Working Example
      • 3.2.3.2. How Lambda Lifting Works in GHC
      • 3.2.3.3. Observing the Effect of Lambda Lifting
      • 3.2.3.4. When to Manually Lambda Lift
      • 3.2.3.5. Summary
    • 3.2.4. Loopification
    • 3.2.5. Manual Worker/Wrapper
    • 3.2.6. Understanding Demand Analysis
  • 3.3. Library Based Changes
    • 3.3.1. Lower Impedance with Better Data Structures
  • 3.4. Library Agnostic Changes
    • 3.4.1. Ordering Data Constructors
    • 3.4.2. Wrangling Lazy Tuples
    • 3.4.3. Appropriate Folding
    • 3.4.4. Avoid Runtime Checks with Parse Don’t Validate:
    • 3.4.5. Data-Oriented Design
    • 3.4.6. Using GHC.Exts
    • 3.4.7. Inlining Pragma and Friends
    • 3.4.8. Specialization
    • 3.4.9. Fusion and Rules
    • 3.4.10. Unboxing
    • 3.4.11. Unpacked Product Types
    • 3.4.12. Avoiding Nested Monad Transformers
    • 3.4.13. Unroll Monad Transformer Stacks
    • 3.4.14. The OneShot Monad Trick
    • 3.4.15. Continuation Passing Style
    • 3.4.16. Using Levity Polymorphism
    • 3.4.17. Using Backpack to Unroll Data Structures

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