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nbirillonbirillo
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Add warm up example
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4 files changed

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‎.run/check-jvm-warmup.run.xml‎

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<component name="ProjectRunConfigurationManager">
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<configuration default="false" name="Check JVM warmup" type="GradleRunConfiguration" factoryName="Gradle">
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<ExternalSystemSettings>
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<option name="executionName" />
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<option name="externalProjectPath" value="$PROJECT_DIR$" />
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<option name="externalSystemIdString" value="GRADLE" />
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<option name="scriptParameters" value="" />
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<option name="taskDescriptions">
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<list />
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</option>
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<option name="taskNames">
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<list>
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<option value="jmh" />
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</list>
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</option>
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<option name="vmOptions" />
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</ExternalSystemSettings>
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<ExternalSystemDebugServerProcess>true</ExternalSystemDebugServerProcess>
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<ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
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<DebugAllEnabled>false</DebugAllEnabled>
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<ForceTestExec>false</ForceTestExec>
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<method v="2" />
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</configuration>
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</component>

‎build.gradle.kts‎

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plugins {
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kotlin("jvm") version "1.8.21"
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id("me.champeau.jmh") version "0.7.1"
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}
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group = "org.example"
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dependencies {
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implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.2")
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val jmhVersion = "1.36"
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implementation("org.openjdk.jmh:jmh-core:$jmhVersion")
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implementation("org.openjdk.jmh:jmh-generator-annprocess:$jmhVersion")
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testImplementation(kotlin("test"))
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}
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‎src/jmh/kotlin/cub/BenchmarkRunner.kt‎

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package cub
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import cub.jvm.BacktrackingSudokuSolver
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import org.openjdk.jmh.annotations.*
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import java.util.concurrent.TimeUnit
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/**
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* Runs Check JVM warmup task from idea configurations
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* to see the difference between first iterations and the next ones
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* To see the difference, just check Fork: N of 3 sections, e.g.
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*
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* # Fork: 1 of 3
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* Iteration 1: 27041458.000 ns/op
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* Iteration 2: 1750.000 ns/op
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* Iteration 3: 1750.000 ns/op
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* Iteration 4: 625.000 ns/op
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* Iteration 5: 1125.000 ns/op
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* Iteration 6: 791.000 ns/op
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* Iteration 7: 958.000 ns/op
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* Iteration 8: 792.000 ns/op
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* Iteration 9: 750.000 ns/op
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* Iteration 10: 1084.000 ns/op
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*
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* Here we can see that the first iteration takes more time than all others.
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* We see different time between attempts, it is ok since the processor spents time for time measurement operations,
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* it affects to the results, but the time here is in nano secs, the difference is not significant.
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**/
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open class BenchmarkRunner {
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companion object {
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private const val BENCHMARK_ITERATIONS = 10
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private const val BENCHMARK_FORKS = 3
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private const val BENCHMARK_WARMUPS = 0
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}
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@Benchmark
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@BenchmarkMode(Mode.SingleShotTime)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@Measurement(iterations = BENCHMARK_ITERATIONS)
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@Fork(value = BENCHMARK_FORKS, warmups = BENCHMARK_WARMUPS)
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fun solveSudoku() {
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val solver = BacktrackingSudokuSolver()
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solver.solve()
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}
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}

‎src/main/kotlin/cub/jvm/BacktrackingSudokuSolver.kt‎

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package cub.jvm
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// Just a simple class with some computations
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class BacktrackingSudokuSolver {
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fun printBoard() {
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board.forEach { row ->
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row.forEach { print("$it ") }
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println()
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}
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}
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fun solve(): Boolean {
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board.forEachIndexed { i, row ->
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row.forEachIndexed { j, column ->
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if (board[i][j] == NO_VALUE) {
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for (k in MIN_VALUE..MAX_VALUE) {
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board[i][j] = k
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if (isValid(i, j) && solve()) {
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return true
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}
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board[i][j] = NO_VALUE
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}
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return false
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}
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}
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}
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return true
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}
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private fun isValid(row: Int, column: Int): Boolean {
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return rowConstraint(row) &&
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columnConstraint(column) &&
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subsectionConstraint(row, column)
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}
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private fun subsectionConstraint(row: Int, column: Int): Boolean {
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val constraint = BooleanArray(BOARD_SIZE)
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val subsectionRowStart = row / SUBSECTION_SIZE * SUBSECTION_SIZE
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val subsectionRowEnd = subsectionRowStart + SUBSECTION_SIZE
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val subsectionColumnStart = column / SUBSECTION_SIZE * SUBSECTION_SIZE
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val subsectionColumnEnd = subsectionColumnStart + SUBSECTION_SIZE
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for (r in subsectionRowStart until subsectionRowEnd) {
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for (c in subsectionColumnStart until subsectionColumnEnd) {
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if (!checkConstraint(r, constraint, c)) return false
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}
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}
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return true
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}
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private fun columnConstraint(column: Int): Boolean {
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val constraint = BooleanArray(BOARD_SIZE)
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return (BOARD_START_INDEX until BOARD_SIZE).all { checkConstraint(it, constraint, column) }
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}
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private fun rowConstraint(row: Int): Boolean {
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val constraint = BooleanArray(BOARD_SIZE)
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return (BOARD_START_INDEX until BOARD_SIZE).all { checkConstraint(row, constraint, it) }
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}
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private fun checkConstraint(row: Int, constraint: BooleanArray, column: Int): Boolean {
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if (board[row][column] != NO_VALUE) {
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if (!constraint[board[row][column] - 1]) {
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constraint[board[row][column] - 1] = true
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} else {
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return false
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}
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}
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return true
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}
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companion object {
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private const val BOARD_SIZE = 9
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private const val SUBSECTION_SIZE = 3
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private const val BOARD_START_INDEX = 0
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private const val NO_VALUE = 0
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private const val MIN_VALUE = 1
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private const val MAX_VALUE = 9
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private val board = arrayOf(
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intArrayOf(8, 0, 0, 0, 0, 0, 0, 0, 0),
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intArrayOf(0, 0, 3, 6, 0, 0, 0, 0, 0),
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intArrayOf(0, 7, 0, 0, 9, 0, 2, 0, 0),
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intArrayOf(0, 5, 0, 0, 0, 7, 0, 0, 0),
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intArrayOf(0, 0, 0, 0, 4, 5, 7, 0, 0),
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intArrayOf(0, 0, 0, 1, 0, 0, 0, 3, 0),
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intArrayOf(0, 0, 1, 0, 0, 0, 0, 6, 8),
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intArrayOf(0, 0, 8, 5, 0, 0, 0, 1, 0),
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intArrayOf(0, 9, 0, 0, 0, 0, 4, 0, 0)
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)
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}
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}

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