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https://issues.apache.org/jira/browse/YARN-10178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17456774#comment-17456774
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Eric Payne commented on YARN-10178:
-----------------------------------
bq. I believe it is not a problem, as we are not making a copy, but creating
new objects out of queues,
[~gandras], after looking more closely, I see that you are correct. The
following copies each object from {{queues}} into a new object of
{{PriorityQueueResourcesForSorting}} and puts it in the new list.
{code:java}
List<PriorityQueueResourcesForSorting> sortedQueueResources =
queues.stream().
map(queue -> new PriorityQueueResourcesForSorting(queue)).
collect(Collectors.toList());
{code}
And as you pointed out, {{absoluteUsedCapacity}}, {{usedCapacity}}, and
{{absoluteCapacity}} are all floats so their value is copied in the constructor
of {{PriorityQueueResourcesForSorting}}. The only remaining value used for
comparison is {{configuredMinResource}}, but I don't expect that to change
unless manually refreshed.
I would feel better if there were a way to test this with a unit test. I'll
keep thinking about it.
> Global Scheduler async thread crash caused by 'Comparison method violates its
> general contract'
> -----------------------------------------------------------------------------------------------
>
> Key: YARN-10178
> URL: https://issues.apache.org/jira/browse/YARN-10178
> Project: Hadoop YARN
> Issue Type: Bug
> Components: capacity scheduler
> Affects Versions: 3.2.1
> Reporter: tuyu
> Assignee: Qi Zhu
> Priority: Major
> Attachments: YARN-10178.001.patch, YARN-10178.002.patch,
> YARN-10178.003.patch, YARN-10178.004.patch, YARN-10178.005.patch
>
>
> Global Scheduler Async Thread crash stack
> {code:java}
> ERROR org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Received
> RMFatalEvent of type CRITICAL_THREAD_CRASH, caused by a critical thread,
> Thread-6066574, that exited unexpectedly: java.lang.IllegalArgumentException:
> Comparison method violates its general contract!
> at
> java.util.TimSort.mergeHi(TimSort.java:899)
> at java.util.TimSort.mergeAt(TimSort.java:516)
> at java.util.TimSort.mergeForceCollapse(TimSort.java:457)
> at java.util.TimSort.sort(TimSort.java:254)
> at java.util.Arrays.sort(Arrays.java:1512)
> at java.util.ArrayList.sort(ArrayList.java:1462)
> at java.util.Collections.sort(Collections.java:177)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.policy.PriorityUtilizationQueueOrderingPolicy.getAssignmentIterator(PriorityUtilizationQueueOrderingPolicy.java:221)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.sortAndGetChildrenAllocationIterator(ParentQueue.java:777)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.assignContainersToChildQueues(ParentQueue.java:791)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.assignContainers(ParentQueue.java:623)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateOrReserveNewContainers(CapacityScheduler.java:1635)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateContainerOnSingleNode(CapacityScheduler.java:1629)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateContainersToNode(CapacityScheduler.java:1732)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.allocateContainersToNode(CapacityScheduler.java:1481)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.schedule(CapacityScheduler.java:569)
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler$AsyncScheduleThread.run(CapacityScheduler.java:616)
> {code}
> JAVA 8 Arrays.sort default use timsort algo, and timsort has few require
> {code:java}
> 1.x.compareTo(y) != y.compareTo(x)
> 2.x>y,y>z --> x > z
> 3.x=y, x.compareTo(z) == y.compareTo(z)
> {code}
> if not Arrays paramters not satify this require,TimSort will throw
> 'java.lang.IllegalArgumentException'
> look at PriorityUtilizationQueueOrderingPolicy.compare function,we will know
> Capacity Scheduler use this these queue resource usage to compare
> {code:java}
> AbsoluteUsedCapacity
> UsedCapacity
> ConfiguredMinResource
> AbsoluteCapacity
> {code}
> In Capacity Scheduler Global Scheduler AsyncThread use
> PriorityUtilizationQueueOrderingPolicy function to choose queue to assign
> container,and construct a CSAssignment struct, and use
> submitResourceCommitRequest function add CSAssignment to backlogs
> ResourceCommitterService will tryCommit this CSAssignment,look tryCommit
> function,there will update queue resource usage
> {code:java}
> public boolean tryCommit(Resource cluster, ResourceCommitRequest r,
> boolean updatePending) {
> long commitStart = System.nanoTime();
> ResourceCommitRequest<FiCaSchedulerApp, FiCaSchedulerNode> request =
> (ResourceCommitRequest<FiCaSchedulerApp, FiCaSchedulerNode>) r;
>
> ...
> boolean isSuccess = false;
> if (attemptId != null) {
> FiCaSchedulerApp app = getApplicationAttempt(attemptId);
> // Required sanity check for attemptId - when async-scheduling enabled,
> // proposal might be outdated if AM failover just finished
> // and proposal queue was not be consumed in time
> if (app != null && attemptId.equals(app.getApplicationAttemptId())) {
> if (app.accept(cluster, request, updatePending)
> && app.apply(cluster, request, updatePending)) { // apply this
> resource
> ...
> }
> }
> }
> return isSuccess;
> }
> }
> {code}
> {code:java}
> public boolean apply(Resource cluster, ResourceCommitRequest<FiCaSchedulerApp,
> FiCaSchedulerNode> request, boolean updatePending) {
> ...
> if (!reReservation) {
> getCSLeafQueue().apply(cluster, request);
> }
> ...
> }
> {code}
> LeafQueue.apply invok allocateResource
> {code:java}
> void allocateResource(Resource clusterResource,
> Resource resource, String nodePartition) {
> try {
> writeLock.lock(); // only lock leaf queue lock
> queueUsage.incUsed(nodePartition, resource);
>
> ++numContainers;
>
> CSQueueUtils.updateQueueStatistics(resourceCalculator, clusterResource,
> this, labelManager, nodePartition); // there will update queue
> statistics
> } finally {
> writeLock.unlock();
> }
> }
> {code}
> we found ResourceCommitterService will only lock leaf queue to update queue
> statistics, but AsyncThread use sortAndGetChildrenAllocationIterator only
> lock queue root queue lock
> {code:java}
> ParentQueue.java
> private Iterator<CSQueue> sortAndGetChildrenAllocationIterator(
> String partition) {
> try {
> readLock.lock();
> return queueOrderingPolicy.getAssignmentIterator(partition);
> } finally {
> readLock.unlock();
> }
> }
> {code}
> so if multi async thread compare queue usage statistics and
> ResourceCommitterService apply leaf queue change statistics concurrent, will
> break TimSort algo required, and cause thread crash
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