cppgc: Add binary trees benchmark

Change-Id: I4886923bd3b2c29f5f317fbfab078af4d5dd8510
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3289156
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77981}

test/benchmarks/cpp/cppgc/BUILD.gn

@@ -57,4 +57,21 @@ if (v8_enable_google_benchmark) {
       deps += [ "../../../..:v8_for_testing" ]
     }
   }
+
+  v8_executable("cppgc_binary_trees_perf") {
+    testonly = true
+
+    configs = [
+      "../../../..:external_config",
+      "../../../..:internal_config_base",
+      "../../../..:cppgc_base_config",
+    ]
+    sources = [ "binary-trees_perf.cc" ]
+    deps = [ ":cppgc_benchmark_support" ]
+    if (cppgc_is_standalone) {
+      deps += [ "../../../..:cppgc_for_testing" ]
+    } else {
+      deps += [ "../../../..:v8_for_testing" ]
+    }
+  }
 }

test/benchmarks/cpp/cppgc/binary-trees_perf.cc

+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <iostream>
+
+#include "include/cppgc/allocation.h"
+#include "include/cppgc/garbage-collected.h"
+#include "include/cppgc/heap.h"
+#include "include/cppgc/persistent.h"
+#include "include/cppgc/visitor.h"
+#include "src/base/macros.h"
+#include "src/heap/cppgc/object-allocator.h"
+#include "test/benchmarks/cpp/cppgc/benchmark_utils.h"
+#include "third_party/google_benchmark/src/include/benchmark/benchmark.h"
+
+namespace {
+
+// Implementation of the binary trees benchmark of the computer language
+// benchmarks game. See
+//   https://benchmarksgame-team.pages.debian.net/benchmarksgame/performance/binarytrees.html
+
+class BinaryTrees : public cppgc::internal::testing::BenchmarkWithHeap {
+ public:
+  BinaryTrees() { Iterations(1); }
+};
+
+class TreeNode final : public cppgc::GarbageCollected<TreeNode> {
+ public:
+  void Trace(cppgc::Visitor* visitor) const {
+    visitor->Trace(left_);
+    visitor->Trace(right_);
+  }
+
+  const TreeNode* left() const { return left_; }
+  void set_left(TreeNode* node) { left_ = node; }
+  const TreeNode* right() const { return right_; }
+  void set_right(TreeNode* node) { right_ = node; }
+
+  size_t Check() const {
+    return left() ? left()->Check() + right()->Check() + 1 : 1;
+  }
+
+ private:
+  cppgc::Member<TreeNode> left_;
+  cppgc::Member<TreeNode> right_;
+};
+
+TreeNode* CreateTree(cppgc::AllocationHandle& alloc_handle, size_t depth) {
+  auto* node = cppgc::MakeGarbageCollected<TreeNode>(alloc_handle);
+  if (depth > 0) {
+    node->set_left(CreateTree(alloc_handle, depth - 1));
+    node->set_right(CreateTree(alloc_handle, depth - 1));
+  }
+  return node;
+}
+
+void Loop(cppgc::AllocationHandle& alloc_handle, size_t iterations,
+          size_t depth) {
+  size_t check = 0;
+  for (size_t item = 0; item < iterations; ++item) {
+    check += CreateTree(alloc_handle, depth)->Check();
+  }
+  std::cout << iterations << "\t  trees of depth " << depth
+            << "\t check: " << check << std::endl;
+}
+
+void Trees(cppgc::AllocationHandle& alloc_handle, size_t max_depth) {
+  // Keep the long-lived tree in a Persistent to allow for concurrent GC to
+  // immediately find it.
+  cppgc::Persistent<TreeNode> long_lived_tree =
+      CreateTree(alloc_handle, max_depth);
+
+  constexpr size_t kMinDepth = 4;
+  const size_t max_iterations = 16 << max_depth;
+  for (size_t depth = kMinDepth; depth <= max_depth; depth += 2) {
+    const size_t iterations = max_iterations >> depth;
+    Loop(alloc_handle, iterations, depth);
+  }
+
+  std::cout << "long lived tree of depth " << max_depth << "\t "
+            << "check: " << long_lived_tree->Check() << "\n";
+}
+
+void RunBinaryTrees(cppgc::Heap& heap) {
+  const size_t max_depth = 21;
+
+  auto& alloc_handle = heap.GetAllocationHandle();
+
+  const size_t stretch_depth = max_depth + 1;
+  std::cout << "stretch tree of depth " << stretch_depth << "\t "
+            << "check: " << CreateTree(alloc_handle, stretch_depth)->Check()
+            << std::endl;
+
+  Trees(alloc_handle, max_depth);
+}
+
+}  // namespace
+
+BENCHMARK_F(BinaryTrees, V1)(benchmark::State& st) {
+  for (auto _ : st) {
+    USE(_);
+    RunBinaryTrees(heap());
+  }
+}