Mastering High Performance with Kotlin: Overcome performance difficulties in Kotlin with a range of exciting techniques and solutions

308 Pages·2018·12.25 MB·English

by  Igor Kucherenko

Mastering High Performance
with Kotlin
Overcome performance difficulties in Kotlin with a range of
exciting techniques and solutions
Igor Kucherenko
BIRMINGHAM - MUMBAI
Mastering High Performance with Kotlin
Copyright © 2018 Packt Publishing
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ISBN 978-1-78899-664-8
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Contributors
About the author
Igor Kucherenko is an Android developer at Techery, a software development company
that uses Kotlin as the main language for Android development. Currently, he lives in
Ukraine, where he is a speaker in the Kotlin Dnipro Community, which promotes Kotlin
and shares knowledge with audiences at meetups. You can find his articles about Kotlin
and Android development on Medium and a blog for Yalantis, where he worked
previously.
I'd like to thank my colleague for sharing knowledge, and Packt Publishing for the
opportunity to write this book; Russell Snyder for his help with many details; my wife for
her patience while I was writing this book.
About the reviewer
Ganesh Samarthyam is a co-founder of CodeOps Technologies, a software technology,
consultancy, and training company based in Bangalore. He has 16 years of experience in the
IT industry, and his latest book, Refactoring for Software Design Smells: Managing Technical
Debt by Morgan Kaufmann/Elsevier, has been translated to languages such as Korean and
Chinese. Ganesh loves exploring anything and everything about technology in his free
time.
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Table of Contents
Preface 1
Chapter 1: Identifying Performance Bottlenecks 6
Reasons for performance issues 6
Memory management 7
Garbage collection 8
Working principles of the garbage collector 8
Impacts of garbage collection 10
Heap fragmentation 10
Finalization 11
Resource leaks 14
Memory leaks 16
String pool 22
Memory model 25
The problem of concurrency and parallelism 26
Java Memory Model (JMM) 27
Synchronization 29
Slow rendering 30
Device refresh rate 30
Frame rate 31
Summary 33
Chapter 2: Identifying Indicators of Performance Issues 34
Benchmarking 35
Microbenchmarks 35
Java Microbenchmark Harness (JMH) 36
Benchmark modes 40
Benchmark time units 42
Benchmark state 43
State scope 44
Fixture methods 44
Levels of fixture methods 46
Writing good benchmarks 46
The pitfalls of loops 46
Dead Code Elimination 48
Using black holes 49
Constant folding 50
Kotlin benchmarks 51
IDEA JMH plugin 53
General performance metrics 54
Types of performance testing 54
Performance testing process 55
Table of Contents
Overview of performance testing tools 56
JMeter 56
Fabric 58
Summary 59
Chapter 3: Learning How to Use Profiling Tools 60
Memory profiling 60
Memory Viewer 61
HProf 63
Eclipse Memory Analyzer Tool 65
Histogram 68
Shallow and Retained Heap 69
Dominator Tree 71
Top Consumers 71
Analyzing class loaders 73
Android Studio Memory Profiler 74
Memory categories 76
Recording memory allocation 76
Threads profiling 80
Threads viewer 80
Frames pane 81
The Threads pane 83
Thread profiling in the MAT 84
Threads Overview 84
Thread Details 85
CPU Profiler in Android Studio 85
Call Chart and Flame Chart tabs 87
Top Down and Bottom Up tabs 88
Summary 88
Chapter 4: Functional Approach 89
Functional programming 89
Declarative versus imperative 91
Pure functions 92
First-class functions 93
Higher-order functions 96
Function composition 99
Lambdas 101
Closures 102
Typeclasses 103
Arrow library 103
Functor 104
Monad 107
Immutability 115
Inspecting functional features 116
Inline versus non-inline 116
Capturing and non-capturing lambdas 121
[ ii ]
Table of Contents
Summary 124
Chapter 5: Enhancing the Performance of Collections 125
Data structures 125
Arrays 126
Linked lists 126
Stacks 127
Queues 130
Sets 130
Maps 131
Hash tables 132
Binary search trees 132
Tries 133
Binary heaps 134
Graphs 135
Time complexity 135
Calculating time complexity 136
Time complexity of lists 137
Time complexity of sets 137
Time complexity of queues 138
Time complexity of maps 138
Collections in Kotlin 139
Sequences in Kotlin 143
Summary 146
Chapter 6: Optimizing Access to Properties 147
Fields and properties 147
Backing fields 150
Backing properties 154
@JvmField annotation 157
Compile-time constants 163
Inner classes 166
lateinit 169
Companion objects 173
Summary 177
Chapter 7: Preventing Unnecessary Overhead Using Delegates 178
Types of delegation 179
Explicit delegation 179
Implicit delegation 183
Class delegation 183
Delegated properties 190
Lazy 190
Creating a delegated property 196
Inspecting the lazy function 203
Observable delegates 205
[ iii ]
Table of Contents
Summary 207
Chapter 8: Ranges and Identifying Performance Issues 208
Ranges in Kotlin 208
Utility functions 221
Range benchmarking 224
Summary 231
Chapter 9: Multithreading and Reactive Programming 232
Concurrency and parallelism 232
Reactive programming 238
Coroutines 250
Setting up a project 251
The launch function 251
The async function 254
The buildSequence function 256
The suspendingSequence function 257
The produce function 259
Coroutines with reactive programming 259
Summary 260
Chapter 10: Best Practices 261
The disposable pattern 261
Immutability 263
Data classes 263
The String pool 266
StringBuilder 267
Functional programming 268
Declarative versus imperative 269
Pure functions 269
First-class functions 269
Higher-order functions 270
Inline functions 271
Function composition 272
Capturing lambdas 274
Collections 275
Properties 275
Backing properties 276
@JvmField annotation 277
Top-level members 278
Compile-time constants 279
The lateinit modifier 280
Delegation 281
Singleton delegate object 281
The lazy funcation with unsafe thread mode 282
[ iv ]