zerolbsony commented on code in PR #17279: URL: https://github.com/apache/iotdb/pull/17279#discussion_r2944123825
########## iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/utils/rateLimiter/LeakyBucketRateLimiter.java: ########## @@ -0,0 +1,115 @@ +/* + * 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.iotdb.commons.utils.rateLimiter; + +import java.util.concurrent.atomic.AtomicLong; +import java.util.concurrent.locks.LockSupport; + +/** + * A global leaky-bucket rate limiter for bytes throughput. Features: - Strict throughput limiting + * (no burst) - Smooth bandwidth shaping - Thread-safe - Fair for multi-thread - Low contention + */ +public class LeakyBucketRateLimiter { + /** bytes per second */ + private volatile long bytesPerSecond; + + /** start time */ + private final long startTimeNs; + + /** total consumed bytes */ + private final AtomicLong totalBytes = new AtomicLong(0); + + public LeakyBucketRateLimiter(long bytesPerSecond) { + if (bytesPerSecond <= 0) { + throw new IllegalArgumentException("bytesPerSecond must be > 0"); + } + this.bytesPerSecond = bytesPerSecond; + this.startTimeNs = System.nanoTime(); + } + + /** + * Acquire permission for reading bytes. + * + * <p>This method will block if reading too fast. + */ + public void acquire(long bytes) { + if (bytes <= 0) { + return; + } + + long currentTotal = totalBytes.addAndGet(bytes); + + long expectedTimeNs = expectedTimeNs(currentTotal); + long now = System.nanoTime(); + + long sleepNs = expectedTimeNs - now; + + if (sleepNs > 0) { + LockSupport.parkNanos(sleepNs); + } + } + + /** + * Try acquire without blocking. + * + * @return true if allowed immediately + */ + public boolean tryAcquire(long bytes) { + if (bytes <= 0) { + return true; + } + + long currentTotal = totalBytes.addAndGet(bytes); + + long expectedTimeNs = expectedTimeNs(currentTotal); + long now = System.nanoTime(); + + if (expectedTimeNs <= now) { + return true; + } + + // rollback + totalBytes.addAndGet(-bytes); + return false; + } + + /** Update rate dynamically. */ + public void setRate(long newBytesPerSecond) { + if (newBytesPerSecond <= 0) { + throw new IllegalArgumentException("bytesPerSecond must be > 0"); + } + this.bytesPerSecond = newBytesPerSecond; + } + + /** Current rate. */ + public long getRate() { + return bytesPerSecond; + } + + /** Total bytes processed. */ + public long getTotalBytes() { + return totalBytes.get(); + } + + /** Expected time based on bytes processed. */ + private long expectedTimeNs(long totalBytes) { + return startTimeNs + (totalBytes * 1_000_000_000L) / bytesPerSecond; Review Comment: Changed yet -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
