s1monw commented on code in PR #12199: URL: https://github.com/apache/lucene/pull/12199#discussion_r1136706886
########## lucene/core/src/java/org/apache/lucene/index/ConcurrentApproximatePriorityQueue.java: ########## @@ -0,0 +1,140 @@ +/* + * 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.lucene.index; + +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; +import java.util.function.Predicate; + +/** + * Concurrent version of {@link ApproximatePriorityQueue}, which trades a bit more of ordering for + * better concurrency by maintaining 8 sub {@link ApproximatePriorityQueue}s that are locked + * independently. + */ +final class ConcurrentApproximatePriorityQueue<T> { + + /** Keeping 8 queues should already help a lot compared to a single one. */ + static final int CONCURRENCY = 8; + + private static final int MASK = 0x07; + + final Lock[] locks; + final ApproximatePriorityQueue<T>[] queues; + + ConcurrentApproximatePriorityQueue() { + locks = new Lock[CONCURRENCY]; + @SuppressWarnings({"rawtypes", "unchecked"}) + ApproximatePriorityQueue<T>[] queues = new ApproximatePriorityQueue[CONCURRENCY]; + this.queues = queues; + for (int i = 0; i < CONCURRENCY; ++i) { + locks[i] = new ReentrantLock(); + queues[i] = new ApproximatePriorityQueue<>(); + } + } + + void add(T entry, long weight) { + // Seed the order in which to look at entries based on the current thread. This helps distribute + // entries across queues and gives a bit of thread affinity between entries and threads, which + // can't hurt. + final int threadHash = Thread.currentThread().hashCode(); + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + if (lock.tryLock()) { + try { + queue.add(entry, weight); + return; + } finally { + lock.unlock(); + } + } + } + final int index = threadHash & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + lock.lock(); + try { + queue.add(entry, weight); + } finally { + lock.unlock(); + } + } + + T poll(Predicate<T> predicate) { + final int threadHash = Thread.currentThread().hashCode(); + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + if (lock.tryLock()) { + try { + T entry = queue.poll(predicate); + if (entry != null) { + return entry; + } + } finally { + lock.unlock(); + } + } + } + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + lock.lock(); + try { + T entry = queue.poll(predicate); + if (entry != null) { + return entry; + } + } finally { + lock.unlock(); + } + } + return null; + } + + // Only used for assertions + boolean contains(Object o) { + for (int i = 0; i < CONCURRENCY; ++i) { Review Comment: nitpick can you add a check that assertions are enabled? ########## lucene/core/src/java/org/apache/lucene/index/ConcurrentApproximatePriorityQueue.java: ########## @@ -0,0 +1,140 @@ +/* + * 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.lucene.index; + +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; +import java.util.function.Predicate; + +/** + * Concurrent version of {@link ApproximatePriorityQueue}, which trades a bit more of ordering for + * better concurrency by maintaining 8 sub {@link ApproximatePriorityQueue}s that are locked + * independently. + */ +final class ConcurrentApproximatePriorityQueue<T> { + + /** Keeping 8 queues should already help a lot compared to a single one. */ + static final int CONCURRENCY = 8; + + private static final int MASK = 0x07; + + final Lock[] locks; + final ApproximatePriorityQueue<T>[] queues; + + ConcurrentApproximatePriorityQueue() { + locks = new Lock[CONCURRENCY]; + @SuppressWarnings({"rawtypes", "unchecked"}) + ApproximatePriorityQueue<T>[] queues = new ApproximatePriorityQueue[CONCURRENCY]; + this.queues = queues; + for (int i = 0; i < CONCURRENCY; ++i) { + locks[i] = new ReentrantLock(); + queues[i] = new ApproximatePriorityQueue<>(); + } + } + + void add(T entry, long weight) { + // Seed the order in which to look at entries based on the current thread. This helps distribute + // entries across queues and gives a bit of thread affinity between entries and threads, which + // can't hurt. + final int threadHash = Thread.currentThread().hashCode(); + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + if (lock.tryLock()) { + try { + queue.add(entry, weight); + return; + } finally { + lock.unlock(); + } + } + } + final int index = threadHash & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + lock.lock(); + try { + queue.add(entry, weight); + } finally { + lock.unlock(); + } + } + + T poll(Predicate<T> predicate) { + final int threadHash = Thread.currentThread().hashCode(); + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + if (lock.tryLock()) { + try { + T entry = queue.poll(predicate); + if (entry != null) { + return entry; + } + } finally { + lock.unlock(); + } + } + } + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + lock.lock(); + try { + T entry = queue.poll(predicate); + if (entry != null) { + return entry; + } + } finally { + lock.unlock(); + } + } + return null; + } + + // Only used for assertions + boolean contains(Object o) { + for (int i = 0; i < CONCURRENCY; ++i) { + locks[i].lock(); Review Comment: this is really a nit pick but for methods that use a lock I'd prefer to assign the lock to a local var instead of dereferencing it again in the finally block. ########## lucene/core/src/java/org/apache/lucene/index/ConcurrentApproximatePriorityQueue.java: ########## @@ -0,0 +1,140 @@ +/* + * 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.lucene.index; + +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; +import java.util.function.Predicate; + +/** + * Concurrent version of {@link ApproximatePriorityQueue}, which trades a bit more of ordering for + * better concurrency by maintaining 8 sub {@link ApproximatePriorityQueue}s that are locked + * independently. + */ +final class ConcurrentApproximatePriorityQueue<T> { + + /** Keeping 8 queues should already help a lot compared to a single one. */ + static final int CONCURRENCY = 8; + + private static final int MASK = 0x07; + + final Lock[] locks; + final ApproximatePriorityQueue<T>[] queues; + + ConcurrentApproximatePriorityQueue() { + locks = new Lock[CONCURRENCY]; + @SuppressWarnings({"rawtypes", "unchecked"}) + ApproximatePriorityQueue<T>[] queues = new ApproximatePriorityQueue[CONCURRENCY]; + this.queues = queues; + for (int i = 0; i < CONCURRENCY; ++i) { + locks[i] = new ReentrantLock(); + queues[i] = new ApproximatePriorityQueue<>(); + } + } + + void add(T entry, long weight) { + // Seed the order in which to look at entries based on the current thread. This helps distribute + // entries across queues and gives a bit of thread affinity between entries and threads, which + // can't hurt. + final int threadHash = Thread.currentThread().hashCode(); + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + if (lock.tryLock()) { + try { + queue.add(entry, weight); + return; + } finally { + lock.unlock(); + } + } + } + final int index = threadHash & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + lock.lock(); + try { + queue.add(entry, weight); + } finally { + lock.unlock(); + } + } + + T poll(Predicate<T> predicate) { + final int threadHash = Thread.currentThread().hashCode(); + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + if (lock.tryLock()) { + try { + T entry = queue.poll(predicate); + if (entry != null) { + return entry; + } + } finally { + lock.unlock(); + } + } + } + for (int i = 0; i < CONCURRENCY; ++i) { + final int index = (threadHash + i) & MASK; + final Lock lock = locks[index]; + final ApproximatePriorityQueue<T> queue = queues[index]; + lock.lock(); + try { + T entry = queue.poll(predicate); + if (entry != null) { + return entry; + } + } finally { + lock.unlock(); + } + } + return null; + } + + // Only used for assertions + boolean contains(Object o) { + for (int i = 0; i < CONCURRENCY; ++i) { + locks[i].lock(); + try { + if (queues[i].contains(o)) { + return true; + } + } finally { + locks[i].unlock(); + } + } + return false; + } + + boolean remove(Object o) { + for (int i = 0; i < CONCURRENCY; ++i) { + locks[i].lock(); Review Comment: same here, maybe use a local var for the lock. It really looks cleaner -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
