Hi, I am having an issue with high cpu usage for deactivated apache storm topologies. I can reliably re-create the issue using the steps below but I haven't identified the exact cause or a solution yet. The environment is a storm cluster on which 1 topology is running (The topology is extremely simple, I used the exclamation example). It is INACTIVE. Initially there is normal CPU usage. However, when I kill all topology JVM processes on all supervisors and let Storm restart them again, I find that some time later (~15 minutes) the CPU usage per JVM process rises to nearly 100%. I have tested an ACTIVE topology and this does not happen with it. I have also tested more than one topology and observe the same results when they're in the INACTIVE state. **Steps to re-create:** 1. Run 1 topology on an Apache Storm cluster 2. Deactivate it 3. Kill *all* topology JVM processes on all supervisors (Storm will restart them) 4. Observe the CPU usage on Supervisors rise to nearly 100% for all *INACTIVE* topology JVM processes. **Environment** Apache Storm 1.1.0 running on 3 VMs, one nimbus and 2 supervisors. Cluster Summary: § Supervisors: 2 § Used Slots: 2 § Available Slots: 38 § Total Slots: 40 § Executors: 50 § Tasks: 50 the topology has 2 workers and 50 executors/tasks (threads). **Investigation so far:** Apart from being able to reliably re-create the issue, I have identified, for the affected topology JVM process, the threads using the most CPU. There are 102 threads total in the process, 97 blocked, 5 IN_NATIVE. The threads using the most CPU are identical and there are 23 of them (all in BLOCKED state): Thread 28558: (state = BLOCKED) § sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; information may be imprecise) § java.util.concurrent.locks.LockSupport.parkNanos(long) @bci=11, line=338 (Compiled frame) § com.lmax.disruptor.MultiProducerSequencer.next(int) @bci=82, line=136 (Compiled frame) § com.lmax.disruptor.RingBuffer.next(int) @bci=5, line=260 (Interpreted frame) § org.apache.storm.utils.DisruptorQueue.publishDirect(java.util.ArrayList, boolean) @bci=18, line=517 (Interpreted frame) § org.apache.storm.utils.DisruptorQueue.access$1000(org.apache.storm.utils.DisruptorQueue, java.util.ArrayList, boolean) @bci=3, line=61 (Interpreted frame) § org.apache.storm.utils.DisruptorQueue$ThreadLocalBatcher.flush(boolean) @bci=50, line=280 (Interpreted frame) § org.apache.storm.utils.DisruptorQueue$Flusher.run() @bci=55, line=303 (Interpreted frame) § java.util.concurrent.Executors$RunnableAdapter.call() @bci=4, line=511 (Compiled frame) § java.util.concurrent.FutureTask.run() @bci=42, line=266 (Compiled frame) § java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=95, line=1142 (Compiled frame) § java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=5, line=617 (Interpreted frame) § java.lang.Thread.run() @bci=11, line=745 (Interpreted frame) I identified this thread by using `jstack` to get a thread dump for the process: jstack -F <pid> > jstack<pid>.txt and `top` to identify the threads within the process using the most CPU: top -H -p <pid>
Has anyone come across this or a similar issue before? Any help would be much appreciated. Thanks, Stuart
