leventov commented on a change in pull request #6710: Added an allocation rate metric #6604 URL: https://github.com/apache/incubator-druid/pull/6710#discussion_r240764988
########## File path: core/src/main/java/org/apache/druid/java/util/metrics/AllocationMetricCollector.java ########## @@ -0,0 +1,100 @@ +/* + * 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.druid.java.util.metrics; + +import it.unimi.dsi.fastutil.longs.Long2LongOpenHashMap; +import org.apache.druid.java.util.common.logger.Logger; +import java.lang.management.ManagementFactory; +import java.lang.management.ThreadMXBean; +import java.lang.reflect.Method; +import java.util.Arrays; +import java.util.Map; +import java.util.Optional; +import java.util.stream.Collectors; + +class AllocationMetricCollector +{ + private static final Logger log = new Logger(AllocationMetricCollector.class); + private static Method getThreadAllocatedBytes; + private static ThreadMXBean threadMXBean; + + private Map<Long, Long> previousResults; + private static boolean initialized = false; + + static { + try { + // classes in the sun.* packages are not part of the public/supported Java API and should not be used directly. + threadMXBean = ManagementFactory.getThreadMXBean(); + getThreadAllocatedBytes = threadMXBean.getClass().getMethod("getThreadAllocatedBytes", long[].class); + getThreadAllocatedBytes.setAccessible(true); + getThreadAllocatedBytes.invoke(threadMXBean, (Object) threadMXBean.getAllThreadIds()); + initialized = true; + } + catch (Exception e) { + log.warn(e, "Cannot initialize %s", AllocationMetricCollector.class.getName()); + } + } + + AllocationMetricCollector() + { + try { + if (initialized) { + previousResults = new Long2LongOpenHashMap(); + } + } + catch (Exception e) { + log.warn(e, "Cannot initialize %s", AllocationMetricCollector.class.getName()); + } + } + + public Optional<Long> calculateDelta() + { + if (!initialized) { + return Optional.empty(); + } + try { + long[] allThreadIds = threadMXBean.getAllThreadIds(); + // the call time depends on number of threads, for 500 threads the estimated time is 4 ms + long[] bytes = (long[]) getThreadAllocatedBytes.invoke(threadMXBean, (Object) allThreadIds); + long sum = 0; + for (int i = 0; i < allThreadIds.length; i++) { + long threadId = allThreadIds[i]; + Long previous = previousResults.get(threadId); + Long current = bytes[i]; + // a) some threads can be terminated and their ids won't be present + // b) if new threads ids can collide with terminated threads ids then the current allocation can be lesser than + // before + if (previous == null || previous > current) { + sum += current; + } else if (previous <= current) { + sum += current - previous; + } + this.previousResults.put(threadId, current); + } + // remove terminated thread ids + previousResults.keySet().retainAll(Arrays.stream(allThreadIds).boxed().collect(Collectors.toSet())); Review comment: Now you do the same work three times: 1) `put()` in the loop 2) `toSet()` - set construction 3) `retainAll()` Instead of doing it once in the loop and then replace the map ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
