seigert / dicts

Naive Open/Closed hashing with benchmarks

Naive Open/Closed Hashing

Implementation of naive int -> any dictionaries with open or closed hashing and benchmarks.

Prerequisites

1. Java >= 1.8, Java 11 recommended:

   ~ > brew install openjdk@11

2. SBT:

   ~ > brew install sbt

Usage

1. To run benchmarks:

   ~ > sbt dicts-benchmark/jmh:run

2. To run tests if necessary:

   ~ > sbt test

Current results

Note: These results use load factor of 1.0 (equals capacity - 1 in code), which is totally unreal and synthetic setting.

Benchmark	(count)	Mode	Cnt	Score		Error	Units
IntDictBenchmark.getClosed	127	avgt	5	0.989	±	0.010	us/op
IntDictBenchmark.getClosed	16535	avgt	5	357.963	±	140.879	us/op
IntDictBenchmark.getClosed	1048575	avgt	5	83261.233	±	5591.723	us/op
IntDictBenchmark.getOpen	127	avgt	5	2.313	±	0.018	us/op
IntDictBenchmark.getOpen	16535	avgt	5	356.559	±	102.913	us/op
IntDictBenchmark.getOpen	1048575	avgt	5	25792.847	±	1204.984	us/op
IntDictBenchmark.missClosed	127	avgt	5	0.932	±	0.009	us/op
IntDictBenchmark.missClosed	16535	avgt	5	437.232	±	23.184	us/op
IntDictBenchmark.missClosed	1048575	avgt	5	111428.388	±	1506.839	us/op
IntDictBenchmark.missOpen	127	avgt	5	12.692	±	0.375	us/op
IntDictBenchmark.missOpen	16535	avgt	5	661.002	±	93.186	us/op
IntDictBenchmark.missOpen	1048575	avgt	5	108710.498	±	5165.610	us/op
IntDictBenchmark.putClosed	127	avgt	5	4.992	±	0.043	us/op
IntDictBenchmark.putClosed	16535	avgt	5	1019.516	±	24.240	us/op
IntDictBenchmark.putClosed	1048575	avgt	5	241567.732	±	9732.676	us/op
IntDictBenchmark.putOpen	127	avgt	5	4.442	±	0.046	us/op
IntDictBenchmark.putOpen	16535	avgt	5	1153.167	±	33.175	us/op
IntDictBenchmark.putOpen	1048575	avgt	5	197239.626	±	1403.676	us/op
IntDictBenchmark.putAllocatedClosed	127	avgt	5	2.568	±	0.135	us/op
IntDictBenchmark.putAllocatedClosed	16535	avgt	5	639.909	±	70.176	us/op
IntDictBenchmark.putAllocatedClosed	1048575	avgt	5	201603.683	±	46738.860	us/op
IntDictBenchmark.putAllocatedOpen	127	avgt	5	3.332	±	0.057	us/op
IntDictBenchmark.putAllocatedOpen	16535	avgt	5	772.453	±	121.198	us/op
IntDictBenchmark.putAllocatedOpen	1048575	avgt	5	164735.061	±	1855.963	us/op
IntDictBenchmark.putAndGetClosed	127	avgt	5	8.139	±	0.090	us/op
IntDictBenchmark.putAndGetClosed	16535	avgt	5	2148.704	±	47.109	us/op
IntDictBenchmark.putAndGetClosed	1048575	avgt	5	452310.557	±	12042.556	us/op
IntDictBenchmark.putAndGetOpen	127	avgt	5	6.905	±	0.268	us/op
IntDictBenchmark.putAndGetOpen	16535	avgt	5	1915.632	±	38.699	us/op
IntDictBenchmark.putAndGetOpen	1048575	avgt	5	343079.123	±	11880.949	us/op
IntDictBenchmark.putAndGetAllocatedClosed	127	avgt	5	5.491	±	0.329	us/op
IntDictBenchmark.putAndGetAllocatedClosed	16535	avgt	5	1542.745	±	735.734	us/op
IntDictBenchmark.putAndGetAllocatedClosed	1048575	avgt	5	340482.744	±	29770.310	us/op
IntDictBenchmark.putAndGetAllocatedOpen	127	avgt	5	11.563	±	0.099	us/op
IntDictBenchmark.putAndGetAllocatedOpen	16535	avgt	5	1852.522	±	619.203	us/op
IntDictBenchmark.putAndGetAllocatedOpen	1048575	avgt	5	333182.320	±	1811.787	us/op

Description

• get*(count) -- gets count of random existing keys from pre-generated dictionary of 2^20 entries;
• miss*(count) -- gets count of random missing keys from pre-generated dictionary of 2^20 entries;
• put*(count) -- put into empty dict count of key-value pair from pre-generated arrays of 2^20 elements;
• putAndGet*(count) -- selects count of keys from pregenerated array, shuffles them and puts 3/4 of them into empty dict, then shuffles again and gets 3/4 of keys;
• *Allocated* -- the same as put*|putAndGet* but with capacity set to count.

System specs:

• CPU: 2,3 GHz 8-Core Intel Core i9
• RAM: 16 GB 2400 MHz DDR4
• OS: macOS Big Sur 11.2.3