Add splay GC benchmark ported from V8/WebKit

benchmarks.yml

@@ -128,6 +128,9 @@ rubykon:
 sudoku:
   desc: sudoku solver
   ractor: true
+splay:
+  desc: Splay tree operations (insert, find, remove) to stress GC.
+  single_file: true
 tinygql:
   desc: TinyGQL gem parsing a large file in pure Ruby
 

benchmarks/splay.rb

@@ -0,0 +1,214 @@
+# Copyright 2009 the V8 project authors. All rights reserved.
+# Copyright (C) 2015 Apple Inc. 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.
+#
+# Ported to Ruby from the V8/WebKit JavaScript benchmark suite.
+# https://browserbench.org/JetStream2.1/Octane/splay.js
+
+require_relative '../harness/loader'
+
+class SplayTree
+  class Node
+    attr_accessor :key, :value, :left, :right
+
+    def initialize(key, value)
+      @key = key
+      @value = value
+      @left = nil
+      @right = nil
+    end
+  end
+
+  def initialize
+    @root = nil
+  end
+
+  def empty?
+    @root.nil?
+  end
+
+  def insert(key, value)
+    if empty?
+      @root = Node.new(key, value)
+      return
+    end
+    splay!(key)
+    return if @root.key == key
+    node = Node.new(key, value)
+    if key > @root.key
+      node.left = @root
+      node.right = @root.right
+      @root.right = nil
+    else
+      node.right = @root
+      node.left = @root.left
+      @root.left = nil
+    end
+    @root = node
+  end
+
+  def remove(key)
+    raise "Key not found: #{key}" if empty?
+    splay!(key)
+    raise "Key not found: #{key}" if @root.key != key
+    removed = @root
+    if @root.left.nil?
+      @root = @root.right
+    else
+      right = @root.right
+      @root = @root.left
+      splay!(key)
+      @root.right = right
+    end
+    removed
+  end
+
+  def find(key)
+    return nil if empty?
+    splay!(key)
+    @root.key == key ? @root : nil
+  end
+
+  def find_max(start_node = nil)
+    return nil if empty?
+    current = start_node || @root
+    current = current.right while current.right
+    current
+  end
+
+  def find_greatest_less_than(key)
+    return nil if empty?
+    splay!(key)
+    if @root.key < key
+      @root
+    elsif @root.left
+      find_max(@root.left)
+    end
+  end
+
+  private
+
+  def splay!(key)
+    return if empty?
+    dummy = Node.new(nil, nil)
+    left = dummy
+    right = dummy
+    current = @root
+    loop do
+      if key < current.key
+        break unless current.left
+        if key < current.left.key
+          tmp = current.left
+          current.left = tmp.right
+          tmp.right = current
+          current = tmp
+          break unless current.left
+        end
+        right.left = current
+        right = current
+        current = current.left
+      elsif key > current.key
+        break unless current.right
+        if key > current.right.key
+          tmp = current.right
+          current.right = tmp.left
+          tmp.left = current
+          current = tmp
+          break unless current.right
+        end
+        left.right = current
+        left = current
+        current = current.right
+      else
+        break
+      end
+    end
+    left.right = current.left
+    right.left = current.right
+    current.left = dummy.right
+    current.right = dummy.left
+    @root = current
+  end
+end
+
+TREE_SIZE = 8000
+MODIFICATIONS = 80
+PAYLOAD_DEPTH = 5
+
+class PayloadNode
+  attr_accessor :left, :right
+  def initialize(left, right)
+    @left = left
+    @right = right
+  end
+end
+
+def generate_payload(depth, tag)
+  if depth == 0
+    { array: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
+      string: "String for key #{tag} in leaf node" }
+  else
+    PayloadNode.new(
+      generate_payload(depth - 1, tag),
+      generate_payload(depth - 1, tag)
+    )
+  end
+end
+
+def insert_new_node(tree, rng)
+  loop do
+    key = rng.rand
+    next if tree.find(key)
+    tree.insert(key, generate_payload(PAYLOAD_DEPTH, key.to_s))
+    return key
+  end
+end
+
+def splay_setup(rng)
+  tree = SplayTree.new
+  TREE_SIZE.times { insert_new_node(tree, rng) }
+  tree
+end
+
+def splay_run(tree, rng)
+  MODIFICATIONS.times do
+    key = insert_new_node(tree, rng)
+    greatest = tree.find_greatest_less_than(key)
+    if greatest
+      tree.remove(greatest.key)
+    else
+      tree.remove(key)
+    end
+  end
+end
+
+rng = Random.new(42)
+tree = splay_setup(rng)
+
+run_benchmark(200) do
+  50.times { splay_run(tree, rng) }
+end