Description Nathan Reynolds 2013-03-16 14:03:09 EDT

I noticed that Eclipse IDE will create a lot of short-lived threads.  If this happens too quickly, then Eclipse will report out of native memory and can not create a new thread.  From there, the IDE's health degrades quickly and becomes unusable.  It eventually has to be killed.

The problem is that each time a thread is created, the address range for its stack is allocated.  When the thread dies, the stack space is not cleaned up immediately by the JVM.  Instead, the stack space won't be cleaned up until the next full GC.  These dead stacks accumulate and cause the above error.  Unfortunately, the JVM won't trigger a full GC if it can't find space for a new thread's stack.

The solution is to use thread pools for short-lived threads.  This will not only prevent the error, but it will also improve performance since a thread can immediately begin executing the task.

I used BTrace to record the call stack each time Thread.start() is called.  I then aggregated these call stacks into a tree (attached).  The numbers in () tell how many threads were created on that branch of the tree.  The BTrace script detected 1562 threads started!  66% of the threads are being created in org.eclipse.jface.text.source.projection.ProjectionSummary$Summarizer.<init>.

Here's a list of the top offenders.  I am not sure which areas these belong to.  Please file a separate bug for each one.  I suspect some of these could be grouped together.

(1027) org.eclipse.jface.text.source.projection.ProjectionSummary$Summarizer.<init>
(114) org.eclipse.jdt.internal.ui.infoviews.AbstractInfoView.computeAndDoSetInput
(103) org.eclipse.jface.text.contentassist.ContentAssistant$AutoAssistListener.start
(97) org.eclipse.jface.text.contentassist.AdditionalInfoController$Timer.<init>
(43) java.util.Timer.<init>
(36) org.eclipse.jface.text.TextViewerHoverManager.computeInformation
(30) java.lang.ref.Finalizer$1.run
(23) org.eclipse.core.internal.jobs.WorkerPool.jobQueued
(21) org.eclipse.jface.text.reconciler.AbstractReconciler.startReconciling
(15) org.eclipse.jdt.internal.compiler.ProcessTaskManager.<init>
(9) org.eclipse.jface.text.source.AnnotationModel.cleanup