JmsConsumer thread hogs CPU even when no updates are present in the queue

[aciapetti]

Using the Docker version of fcrepo-camel-toolbox (latest version) I got a 100% CPU usage for one of the container cores even when no update is present in the Fedora ActiveMQ queue.

My configuration of the toolbox is:

fcrepo.authHost=fcrepo
fcrepo.authUsername=fedoraAdmin
fcrepo.authPassword=
ldpath.transform.path=file:///config/ldpath/teca.ldpath
jms.brokerUrl=tcp://fcrepo:61616
solr.indexing.enabled=true
solr.baseUrl=http://solr:8983/solr/fcrepo
triplestore.indexing.enabled=true
triplestore.baseUrl=http://fuseki:3030/fcrepo
reindexing.rest.host=0.0.0.0

Output of the htop command:
1842434 root 20 0 13,5g 729244 25604 S 100,0 2,2 162:10.88 java -jar /usr/local/fcrepo-camel-toolbox/driver.jar -c /config/toolbox-configuration.properties (CPU is at 100% for at least one of my 8 cores)

Is it possible to lower the polling frequency on the JMS queue using the configuration?
Is it in some way related to the Thread.onSpinWait() cycle in the Driver class?

Thanks Andrea

[whikloj]

Hi @aciapetti, it would appear it is related to the Thread.onSpinWait() loop as you mentioned.

--- Execution profile ---
Total samples       : 1306

--- 12840000000 ns (98.32%), 1284 samples
  [ 0] org.springframework.context.support.AbstractApplicationContext.isRunning
  [ 1] org.fcrepo.camel.toolbox.app.Driver.call
  [ 2] org.fcrepo.camel.toolbox.app.Driver.call
  [ 3] picocli.CommandLine.executeUserObject
  [ 4] picocli.CommandLine.access$1200
  [ 5] picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent
  [ 6] picocli.CommandLine$RunLast.handle
  [ 7] picocli.CommandLine$RunLast.handle
  [ 8] picocli.CommandLine$AbstractParseResultHandler.execute
  [ 9] picocli.CommandLine.execute
  [10] org.fcrepo.camel.toolbox.app.Driver.main

...

          ns  percent  samples  top
  ----------  -------  -------  ---
 12840000000   98.32%     1284  org.springframework.context.support.AbstractApplicationContext.isRunning
   120000000    0.92%       12  org.fcrepo.camel.toolbox.app.Driver.call
    30000000    0.23%        3  __psynch_cvwait
    20000000    0.15%        2  org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener
    10000000    0.08%        1  BiasedLocking::revoke_and_rebias
    10000000    0.08%        1  java.lang.AbstractStringBuilder.append
    10000000    0.08%        1  CollectedHeap::array_allocate
    10000000    0.08%        1  org.springframework.jms.listener.AbstractMessageListenerContainer.commitIfNecessary
    10000000    0.08%        1  java.util.concurrent.CopyOnWriteArrayList.iterator

If you have a recommendation, we will happily take it.

I'll add this to the list of things to have a look at. This app will need to change to be more spring-boot like with the latest Camel versions, but no one has been willing to take a look at that yet.