java-collection-overhead
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gaul
Demonstrate overheads for various Java Collection implementations.
Java Collection Overhead
Demonstrate overheads for various Java Collection implementations. This
measures storing int data, excluding the cost of boxed Integers.
This compares built-in Java, fastutil,
Guava, and
Trove collections.
Tested with JDK 8 on x86-64 Linux with
compressed Oops
(default).
Results
Measure per-entry overhead by creating a single large collection. Measure
per-instance overhead by creating many small collections with a single element.
This over-reports per-instance overhead by 4 bytes due to
Collection<Collection>
| Collection | Per-entry Overhead (bytes) |
Per-instance Overhead (bytes) |
|---|---|---|
| List | ||
| ArrayList | 4 | 52 |
| ImmutableList | 4 | 20 |
| LinkedList | 24 | 60 |
| TIntArrayList | 4 | 52 |
| TIntLinkedList | 24 | 60 |
| Map | ||
| Cache | 56 | 916 |
| ConcurrentHashMap | 40 | 180 |
| ConcurrentSkipListMap | 36 | 145 |
| EnumMap | n/a | 124 |
| HashMap | 40 | 108 |
| ImmutableMap | 32 | 44 |
| ImmutableRangeMap | 64 | 116 |
| ImmutableSortedMap | 8 | 108 |
| Int2IntAVLTreeMap | 32 | 164 |
| Int2IntLinkedOpenHashMap | 32 | 188 |
| Int2IntOpenHashMap | 16 | 132 |
| Int2IntRBTreeMap | 32 | 452 |
| LinkedHashMap | 48 | 124 |
| LongLongHashMap | 32 | 116 |
| MapMaker | 40 | 244 |
| TIntIntHashMap | 18 | 156 |
| TreeMap | 40 | 92 |
| TreeRangeMap | 120 | 188 |
| Multiset | ||
| ConcurrentHashMultiset | 56 | 220 |
| HashMultiset | 56 | 156 |
| ImmutableMultiset | 32 | 116 |
| LinkedHashMultiset | 64 | 172 |
| TreeMultiset | 56 | 212 |
| Queue | ||
| ArrayDeque | 8 | 108 |
| ConcurrentLinkedDeque | 24 | 76 |
| PriorityQueue | 4 | 60 |
| Set | ||
| ConcurrentSkipListSet | 36 | 161 |
| EnumSet | n/a | 36 |
| HashSet | 40 | 124 |
| ImmutableRangeSet | 60 | 100 |
| ImmutableSet | 12 | 28 |
| ImmutableSortedSet | 4 | 52 |
| IntAVLTreeSet | 32 | 140 |
| IntLinkedOpenHashSet | 24 | 132 |
| IntOpenHashSet | 8 | 84 |
| IntRBTreeSet | 32 | 436 |
| LinkedHashSet | 48 | 140 |
| LongHashSet | 16 | 76 |
| TIntHashSet | 8 | 116 |
| TreeRangeSet | 96 | 180 |
| TreeSet | 40 | 108 |
Collected via:
target/java-collection-overhead --list | grep -v Enum | while read c; do target/java-collection-overhead $c $((8 * 1024 * 1024)) 1 || break; done
target/java-collection-overhead --list | while read c; do target/java-collection-overhead $c 1 $((1024 * 1024)) || break; done
References
- https://github.com/DimitrisAndreou/memory-measurer/blob/master/ElementCostInDataStructures.txt
- https://www.ibm.com/developerworks/java/library/j-codetoheap/
License
Copyright (C) 2018 Andrew Gaul
Licensed under the Apache License, Version 2.0
gaul