merlimat commented on a change in pull request #1682: Added BlockingQueue implementation based on JCtools URL: https://github.com/apache/bookkeeper/pull/1682#discussion_r232114716
########## File path: bookkeeper-common/src/main/java/org/apache/bookkeeper/common/collections/BusyWait.java ########## @@ -0,0 +1,60 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF 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 + * + * http://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 org.apache.bookkeeper.common.collections; + +import java.lang.invoke.MethodHandle; +import java.lang.invoke.MethodHandles; +import java.lang.invoke.MethodType; + +import lombok.experimental.UtilityClass; + +/** + * Utility class to use "Thread.onSpinWait()" when available. + */ +@UtilityClass +public class BusyWait { + + /** + * If available (Java 9+), use intrinsic {@link Thread#onSpinWait} which will + * reduce CPU consumption during the wait, otherwise fallback to regular + * spinning. + */ + public static void onSpinWait() { + if (ON_SPIN_WAIT != null) { + try { + ON_SPIN_WAIT.invokeExact(); + } catch (Throwable t) { + // Ignore + } + } + } + + private static final MethodHandle ON_SPIN_WAIT; + + static { + MethodHandle handle = null; + try { + handle = MethodHandles.lookup().findStatic(Thread.class, "onSpinWait", MethodType.methodType(void.class)); + } catch (Throwable t) { + // Ignore + } Review comment: This is not strictly critical for performance, it's just a way to consume less CPU power. Since it's not available in Java8, I'd rather keep this at debug level to avoid printing the warning every time (eg: even if busywait is not used). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
