Add a benchmark for examining the performance difference between explicitly closing memory segments, versus having them closed by cleaners

src/test/java/io/netty/buffer/api/benchmarks/MemorySegmentClosedByCleanerBenchmark.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2019 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.buffer.api.benchmarks;
+
+import io.netty.buffer.api.Allocator;
+import io.netty.buffer.api.Buf;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.concurrent.CompletableFuture.completedFuture;
+
+@Warmup(iterations = 30, time = 1)
+@Measurement(iterations = 30, time = 1)
+@Fork(value = 5, jvmArgsAppend = { "-XX:+UnlockDiagnosticVMOptions", "-XX:+DebugNonSafepoints" })
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MICROSECONDS)
+@State(Scope.Benchmark)
+public class MemorySegmentClosedByCleanerBenchmark {
+    private static final Allocator direct = Allocator.direct();
+    private static final Allocator withCleaner = Allocator.directWithCleaner();
+
+    @Param({"heavy", "light"})
+    public String workload;
+    public boolean isHeavy;
+
+    @Setup
+    public void setUp() {
+        if ("heavy".equals(workload)) {
+            isHeavy = true;
+        } else if ("light".equals(workload)) {
+            isHeavy = false;
+        } else {
+            throw new IllegalArgumentException("Unsupported workload: " + workload);
+        }
+    }
+
+    @Benchmark
+    public Buf explicitClose() throws Exception {
+        try (Buf buf = process(direct.allocate(256))) {
+            return buf;
+        }
+    }
+
+    @Benchmark
+    public Buf cleanerClose() throws Exception {
+        return process(withCleaner.allocate(256));
+    }
+
+    private Buf process(Buf buffer) throws Exception {
+        // Simulate some async network server thingy, processing the buffer.
+        var tlr = ThreadLocalRandom.current();
+        if (isHeavy) {
+            return completedFuture(buffer.send()).thenApplyAsync(send -> {
+                try (Buf buf = send.receive()) {
+                    while (buf.writableBytes() > 0) {
+                        buf.writeByte((byte) tlr.nextInt());
+                    }
+                    return buf.send();
+                }
+            }).thenApplyAsync(send -> {
+                try (Buf buf = send.receive()) {
+                    byte b = 0;
+                    while (buf.readableBytes() > 0) {
+                        b += buf.readByte();
+                    }
+                    buf.fill(b);
+                    return buf.send();
+                }
+            }).get().receive();
+        } else {
+            while (buffer.writableBytes() > 0) {
+                buffer.writeByte((byte) tlr.nextInt());
+            }
+            byte b = 0;
+            while (buffer.readableBytes() > 0) {
+                b += buffer.readByte();
+            }
+            buffer.fill(b);
+            return buffer;
+        }
+    }
+}