Fix scalability issue due to checkcast on context's invoke operations

microbench/src/main/java/io/netty/microbench/channel/DefaultChannelPipelineDuplexHandlerBenchmark.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2022 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.microbench.channel;
+
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.ChannelPipeline;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.microbench.util.AbstractMicrobenchmark;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Measurement;
+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.TearDown;
+import org.openjdk.jmh.annotations.Threads;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 5, time = 1)
+@State(Scope.Thread)
+public class DefaultChannelPipelineDuplexHandlerBenchmark extends AbstractMicrobenchmark {
+
+    private ChannelPipeline pipeline;
+    private EmbeddedChannel channel;
+
+    @Param({"true", "false"})
+    private boolean duplex;
+
+    @Setup
+    public void setup() {
+        channel = new EmbeddedChannel() {
+            @Override
+            public void runPendingTasks() {
+                // NO-OP to reduce noise on flush
+            }
+        };
+        // disabling auto-read to reduce noise on flush
+        channel.config().setAutoRead(false);
+        pipeline = channel.pipeline();
+        pipeline.addLast(new ChannelInboundHandlerAdapter() {
+            @Override
+            public void channelReadComplete(final ChannelHandlerContext ctx) {
+                ctx.fireChannelReadComplete();
+            }
+        });
+        // Duplex handlers implements both out/in interfaces causing a scalability issue
+        // see https://bugs.openjdk.org/browse/JDK-8180450
+        if (duplex) {
+            pipeline.addLast(new ChannelDuplexHandler() {
+                @Override
+                public void channelReadComplete(final ChannelHandlerContext ctx) {
+                    ctx.fireChannelReadComplete();
+                }
+
+                @Override
+                public void flush(final ChannelHandlerContext ctx) {
+                    ctx.flush();
+                }
+            });
+            pipeline.addLast(new ChannelDuplexHandler() {
+                @Override
+                public void channelReadComplete(final ChannelHandlerContext ctx) {
+                    ctx.flush();
+                }
+            });
+        } else {
+            pipeline.addLast(new ChannelInboundHandlerAdapter() {
+                @Override
+                public void channelReadComplete(final ChannelHandlerContext ctx) {
+                    ctx.fireChannelReadComplete();
+                }
+            });
+            pipeline.addLast(new ChannelOutboundHandlerAdapter() {
+                @Override
+                public void flush(final ChannelHandlerContext ctx) {
+                    ctx.flush();
+                }
+            });
+            pipeline.addLast(new ChannelInboundHandlerAdapter() {
+                @Override
+                public void channelReadComplete(final ChannelHandlerContext ctx) {
+                    ctx.flush();
+                }
+            });
+        }
+    }
+
+    @TearDown
+    public void tearDown() {
+        pipeline.channel().close();
+    }
+
+    @Benchmark
+    public void propagateEvent(Blackhole hole) {
+        hole.consume(pipeline.fireChannelReadComplete());
+    }
+
+    @Benchmark
+    @Threads(4)
+    public void parallelPropagateEvent(Blackhole hole) {
+        hole.consume(pipeline.fireChannelReadComplete());
+    }
+}