[K/N] Add splay benchmark based on the V8 Benchmark Suite.

The benchmark constructs a splay tree, measures the time it takes to performs a number of insertions and removals, and after measurements validates that the splay tree is valid.
2022-05-25 14:10:58 +02:00
parent 3b5179686e
commit ddb140cc51
4 changed files with 320 additions and 2 deletions
@@ -58,6 +58,7 @@ class RingLauncher : Launcher() {
                    "PrimeList.calcDirect" to BenchmarkEntryWithInit.create(::PrimeListBenchmark, { calcDirect() }),
                    "PrimeList.calcEratosthenes" to BenchmarkEntryWithInit.create(::PrimeListBenchmark, { calcEratosthenes() }),
                    "Singleton.access" to BenchmarkEntryWithInit.create(::SingletonBenchmark, { access() }),
+                    "Splay" to BenchmarkEntryWithInitAndValidation.create(::SplayBenchmark, { runSplay() }, { splayTearDown() }),
                    "String.stringConcat" to BenchmarkEntryWithInit.create(::StringBenchmark, { stringConcat() }),
                    "String.stringBuilderConcat" to BenchmarkEntryWithInit.create(::StringBenchmark, { stringBuilderConcat() }),
                    "String.stringBuilderConcatNullable" to BenchmarkEntryWithInit.create(::StringBenchmark, { stringBuilderConcatNullable() }),
@@ -0,0 +1,303 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+// This benchmark is a port of the V8 JavaScript benchmark suite
+// splay benchmark:
+//   https://chromium.googlesource.com/external/v8/+/ba56077937e154aa0adbabd8abb9c24e53aae85d/benchmarks/splay.js
+
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// This benchmark is based on a JavaScript log processing module used
+// by the V8 profiler to generate execution time profiles for runs of
+// JavaScript applications, and it effectively measures how fast the
+// JavaScript engine is at allocating nodes and reclaiming the memory
+// used for old nodes. Because of the way splay trees work, the engine
+// also has to deal with a lot of changes to the large tree object
+// graph.
+
+import kotlin.random.Random
+
+// A splay tree is a self-balancing binary search tree with the additional
+// property that recently accessed elements are quick to access again.
+// It performs basic operations such as insertion, look-up and removal in
+// O(log(n)) amortized time.
+class SplayTree<K: Comparable<K>, V> {
+
+    // Nodes of the splay tree.
+    class Node<K: Comparable<K>, V>(val key: K, val value: V) {
+        var left: Node<K, V>? = null
+        var right: Node<K, V>? = null
+
+        // Performs an ordered traversal of the subtree starting at this SplayTree.Node.
+        fun traverse(f: (Node<K, V>) -> Unit) {
+            var current: Node<K, V>? = this
+            while (current != null) {
+                current.left?.traverse(f)
+                f(current)
+                current = current.right
+            }
+        }
+    }
+
+    // Root of the splay tree.
+    private var root: Node<K, V>? = null
+
+    // Return whether the splay tree is empty.
+    fun isEmpty() = root == null
+
+    // Inserts a node into the tree with the specified key and value if
+    // the tree does not already contain a node with the specified key. If
+    // the value is inserted, it becomes the root of the tree.
+    fun insert(key: K, value: V) {
+        if (isEmpty()) {
+            root = Node(key, value)
+            return
+        }
+        // Splay on the key to move the last node on the search path for
+        // the key to the root of the tree.
+        splay(key)
+        val r = root!!
+        if (r.key == key) {
+            return
+        }
+        val node = Node(key, value)
+        if (key > r.key) {
+            node.left = r
+            node.right = r.right
+            r.right = null
+        } else {
+            node.right = r
+            node.left = r.left
+            r.left = null
+        }
+        root = node
+    }
+
+    // Removes a node with the specified key from the tree if the tree
+    // contains a node with this key. The removed node is returned. If the
+    // key is not found, an exception is thrown.
+    fun remove(key: K): Node<K, V> {
+        if (this.isEmpty()) {
+            throw Exception("Key not found: $key")
+        }
+        splay(key)
+        val r = root!!
+        if (r.key != key) {
+            throw Exception("Key not found: $key")
+        }
+        val removed = r
+        if (r.left == null) {
+            root = r.right
+        } else {
+            val right = r.right
+            root = r.left
+            // Splay to make sure that the new root has an empty right child.
+            splay(key)
+            // Insert the original right child as the right child of the new root.
+            root!!.right = right
+        }
+        return removed
+    }
+
+    // Returns the node having the specified key or null if the tree doesn't contain
+    // a node with the specified key.
+    fun find(key: K): Node<K, V>? {
+        if (isEmpty()) return null
+        splay(key)
+        return if (root!!.key == key) root else null
+    }
+
+    // Returns node having the maximum key value.
+    fun findMax(startNode: Node<K, V>? = null): Node<K, V>? {
+        if (isEmpty()) return null
+        var current = startNode ?: root!!
+        while (current.right != null) {
+            current = current.right!!
+        }
+        return current
+    }
+
+    // Returns node having the maximum key value that is less than the
+    // specified key value.
+    fun findGreatestLessThan(key: K): Node<K, V>? {
+        if (isEmpty()) return null
+        // Splay on the key to move the node with the given key or the last
+        // node on the search path to the top of the tree.
+        splay(key)
+        // Now the result is either the root node or the greatest node in the
+        // left subtree.
+        val r = root!!
+        return if (r.key < key) {
+            root
+        } else if (r.left != null) {
+            findMax(r.left)
+        } else {
+            null
+        }
+    }
+
+    // Returns a list containing all the keys in the tree's nodes.
+    fun exportKeys(): List<K> {
+        val result = mutableListOf<K>()
+        if (!isEmpty()) {
+            root?.traverse { result.add(it.key) }
+        }
+        return result
+    }
+
+    // Perform the splay operation for the given key. Moves the node with
+    // the given key to the top of the tree.  If no node has the given
+    // key, the last node on the search path is moved to the top of the
+    // tree. This is the simplified top-down splaying algorithm from:
+    // "Self-adjusting Binary Search Trees" by Sleator and Tarjan
+    private fun splay(key: K) {
+        if (isEmpty()) return
+        // Create a dummy node.  The use of the dummy node is a bit
+        // counter-intuitive: The right child of the dummy node will hold
+        // the L tree of the algorithm.  The left child of the dummy node
+        // will hold the R tree of the algorithm.  Using a dummy node, left
+        // and right will always be nodes and we avoid special cases.
+        // The key and value for the dummy node will not be used, so we just
+        // use the key and value of the root node for the dummy.
+        val dummy = Node(root!!.key, root!!.value)
+        var left = dummy
+        var right = dummy
+
+        var current = root!!
+        while (true) {
+            if (key < current.key) {
+                if (current.left == null) {
+                    break
+                }
+                if (key < current.left!!.key) {
+                    // Rotate right
+                    val tmp = current.left!!
+                    current.left = tmp.right
+                    tmp.right = current
+                    current = tmp
+                    if (current.left == null) {
+                        break
+                    }
+                }
+                // Link right.
+                right.left = current
+                right = current
+                current = current.left!!
+            } else if (key > current.key) {
+                if (current.right == null) {
+                    break
+                }
+                if (key > current.right!!.key) {
+                    // Rotate left.
+                    val tmp = current.right!!
+                    current.right = tmp.left
+                    tmp.left = current
+                    current = tmp
+                    if (current.right == null) {
+                        break
+                    }
+                }
+                // Link left.
+                left.right = current
+                left = current
+                current = current.right!!
+            } else {
+                break
+            }
+        }
+        // Assemble.
+        left.right = current.left
+        right.left = current.right
+        current.left = dummy.right
+        current.right = dummy.left
+        root = current
+    }
+}
+
+class SplayBenchmark {
+    // Seed random number generator for deterministic "random" number generation.
+    val random = Random(20)
+    val splayTreeSize = 8000;
+    // Different from the original as the surrounding runner is different. We want
+    // enough modifications that GCs will take place and will matter.
+    val splayTreeModifications = 8000;
+    val splayTreePayloadDepth = 5;
+    val splayTree = splaySetup()
+
+    fun generateKey(): Int = random.nextInt()
+
+    fun generatePayloadTree(depth: Int, tag: String): Pair<Any, Any> {
+        return if (depth == 0) {
+            Pair(listOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9), "String for key $tag in leaf node")
+        } else {
+            Pair(generatePayloadTree(depth - 1, tag), generatePayloadTree(depth - 1, tag))
+        }
+    }
+
+    fun insertNewNode(tree: SplayTree<Int, Pair<Any, Any>>, payloadDepth: Int): Int {
+        var key = generateKey()
+        while (tree.find(key) != null) {
+            key = generateKey()
+        }
+        var payload = generatePayloadTree(payloadDepth, "$key")
+        tree.insert(key, payload)
+        return key
+    }
+
+    fun splaySetup(): SplayTree<Int, Pair<Any, Any>> {
+        val result = SplayTree<Int, Pair<Any, Any>>()
+        for (i in 0 until splayTreeSize) insertNewNode(result, splayTreePayloadDepth)
+        return result
+    }
+
+    fun splayTearDown() {
+        val keys = splayTree.exportKeys()
+        val length = keys.size
+        if (length != splayTreeSize) {
+            throw Exception("Splay tree has wrong size")
+        }
+        for (i in 0 until length - 1) {
+            if (keys[i] >= keys[i + 1]) {
+                throw Exception("Splay tree not sorted")
+            }
+        }
+    }
+
+    fun runSplay() {
+        for (i in 0 until splayTreeModifications) {
+            val key = insertNewNode(splayTree, splayTreePayloadDepth)
+            val greatest = splayTree.findGreatestLessThan(key)
+            if (greatest == null) {
+                splayTree.remove(key)
+            } else {
+                splayTree.remove(greatest.key)
+            }
+        }
+    }
+}
@@ -22,7 +22,7 @@ interface AbstractBenchmarkEntry {
    open val useAutoEvaluatedNumberOfMeasure: Boolean
 }

-class BenchmarkEntryWithInit(val ctor: ()->Any, val lambda: (Any) -> Any?): AbstractBenchmarkEntry {
+open class BenchmarkEntryWithInit(val ctor: ()->Any, val lambda: (Any) -> Any?): AbstractBenchmarkEntry {
    companion object {
        inline fun <T: Any> create(noinline ctor: ()->T, crossinline lambda: T.() -> Any?) = BenchmarkEntryWithInit(ctor) { (it as T).lambda() }
    }
@@ -30,6 +30,16 @@ class BenchmarkEntryWithInit(val ctor: ()->Any, val lambda: (Any) -> Any?): Abst
    override val useAutoEvaluatedNumberOfMeasure: Boolean = true
 }

+class BenchmarkEntryWithInitAndValidation(ctor: () -> Any, benchmark: (Any) -> Any?, val validation: (Any) -> Any?)
+    : BenchmarkEntryWithInit(ctor, benchmark) {
+    companion object {
+        inline fun <T: Any> create(noinline ctor: ()->T, crossinline benchmark: T.() -> Any?, crossinline validation: T.() -> Any?)
+                = BenchmarkEntryWithInitAndValidation(ctor, { (it as T).benchmark() }, { (it as T).validation() })
+    }
+
+    override val useAutoEvaluatedNumberOfMeasure: Boolean = true
+}
+
 open class BenchmarkEntry(val lambda: () -> Any?) : AbstractBenchmarkEntry {
    override val useAutoEvaluatedNumberOfMeasure: Boolean = true
 }
@@ -46,10 +46,14 @@ abstract class Launcher {
        var i = repeatNumber
        return if (benchmark is BenchmarkEntryWithInit) {
            cleanup()
-            measureNanoTime {
+            val result = measureNanoTime {
                while (i-- > 0) benchmark.lambda(benchmarkInstance!!)
                cleanup()
            }
+            if (benchmark is BenchmarkEntryWithInitAndValidation) {
+                benchmark.validation(benchmarkInstance!!)
+            }
+            result
        } else if (benchmark is BenchmarkEntry) {
            cleanup()
            measureNanoTime {