Created
July 19, 2015 05:23
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binary search vs linear scan
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| package com.databricks.unsafe.util.benchmark; | |
| import org.openjdk.jmh.annotations.Benchmark; | |
| import org.openjdk.jmh.annotations.Param; | |
| import org.openjdk.jmh.annotations.Scope; | |
| import org.openjdk.jmh.annotations.State; | |
| import org.openjdk.jmh.runner.Runner; | |
| import org.openjdk.jmh.runner.RunnerException; | |
| import org.openjdk.jmh.runner.options.Options; | |
| import org.openjdk.jmh.runner.options.OptionsBuilder; | |
| @State(Scope.Benchmark) | |
| public class BinarySearch { | |
| @Param({"1", "10", "50", "100", "200", "250", "273", "365"}) | |
| public int dayInYear; | |
| private static final int[] arr = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365}; | |
| @Benchmark | |
| public long linearSearch() { | |
| if (dayInYear <= 31) { | |
| return 1; | |
| } else if (dayInYear <= 59) { | |
| return 2; | |
| } else if (dayInYear <= 90) { | |
| return 3; | |
| } else if (dayInYear <= 120) { | |
| return 4; | |
| } else if (dayInYear <= 151) { | |
| return 5; | |
| } else if (dayInYear <= 181) { | |
| return 6; | |
| } else if (dayInYear <= 212) { | |
| return 7; | |
| } else if (dayInYear <= 243) { | |
| return 8; | |
| } else if (dayInYear <= 273) { | |
| return 9; | |
| } else if (dayInYear <= 304) { | |
| return 10; | |
| } else if (dayInYear <= 334) { | |
| return 11; | |
| } else { | |
| return 12; | |
| } | |
| } | |
| @Benchmark | |
| public long binarySearch() { | |
| int index = java.util.Arrays.binarySearch(arr, dayInYear); | |
| return index > 0 ? index - 1 : - index - 2; // zero based | |
| } | |
| public static void main(String[] args) throws RunnerException { | |
| Options opt = new OptionsBuilder() | |
| .include(BinarySearch.class.getSimpleName()) | |
| .warmupIterations(5) | |
| .measurementIterations(5) | |
| .forks(2) | |
| .jvmArgs("-ea") | |
| .build(); | |
| new Runner(opt).run(); | |
| } | |
| } |
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| Benchmark (dayInYear) Mode Cnt Score Error Units | |
| BinarySearch.binarySearch 1 thrpt 4 115347880.155 ± 8520914.477 ops/s | |
| BinarySearch.binarySearch 10 thrpt 4 113654466.772 ± 8625273.222 ops/s | |
| BinarySearch.binarySearch 50 thrpt 4 133030684.937 ± 10710487.122 ops/s | |
| BinarySearch.binarySearch 100 thrpt 4 133953770.632 ± 12634401.850 ops/s | |
| BinarySearch.binarySearch 200 thrpt 4 130781158.940 ± 8043762.686 ops/s | |
| BinarySearch.binarySearch 250 thrpt 4 132553717.324 ± 21414919.596 ops/s | |
| BinarySearch.binarySearch 273 thrpt 4 244471672.528 ± 9463128.602 ops/s | |
| BinarySearch.binarySearch 365 thrpt 4 166535896.580 ± 28047392.033 ops/s | |
| BinarySearch.linearSearch 1 thrpt 4 463719441.329 ± 106581527.249 ops/s | |
| BinarySearch.linearSearch 10 thrpt 4 448299356.497 ± 166163742.716 ops/s | |
| BinarySearch.linearSearch 50 thrpt 4 449009750.056 ± 113741145.284 ops/s | |
| BinarySearch.linearSearch 100 thrpt 4 443775770.080 ± 31449395.157 ops/s | |
| BinarySearch.linearSearch 200 thrpt 4 395199721.525 ± 28370833.771 ops/s | |
| BinarySearch.linearSearch 250 thrpt 4 322339256.287 ± 153877281.219 ops/s | |
| BinarySearch.linearSearch 273 thrpt 4 351028964.278 ± 34651113.649 ops/s | |
| BinarySearch.linearSearch 365 thrpt 4 324125219.514 ± 33060425.949 ops/s |
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