10/4/2023 0 Comments Lock queue lock 52![]() Progress Timer" Id=71 WAITING on (Native Method)Īt 2.figures.ProgressFigure$n(ProgressFigure.java:554) "TimerQueue" Id=78 WAITING on (Native Method)Īt .take(DelayQueue.java:211)Īt (TimerQueue.java:171) waiting on .LockSupport.park(LockSupport.java:175)Īt .AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)Īt .take(ArrayBlockingQueue.java:403)Īt .getTask(ThreadPoolExecutor.java:1067) "KNIME-WFM-Parent-Notifier" Id=79 WAITING on (Native Method) "AWT-Shutdown" Id=82 WAITING on (Native Method)Īt (AWTAutoShutdown.java:295) ![]() waiting on (Object.java:502)Īt .$3.run(MemoryAlertSystem.java:270)Īt (ArrayList.java:317)Īt (ArrayList.java:300)Īt .(NameFilterPanel.java:611)Īt .(NameFilterPanel.java:839)Īt .loadConfiguration(DataColumnSpecFilterPanel.java:184)Īt .loadSettingsFrom(DataColumnSpecFilterNodeDialogPane.java:94)Īt .NodeDialogPane.loadSettingsFrom(NodeDialogPane.java:564)Īt .NodeDialogPane.callDerivedLoadSettingsFrom(NodeDialogPane.java:473)Īt .NodeDialogPane$3.run(NodeDialogPane.java:426)Īt .util.ViewUtils$3.run(ViewUtils.java:351)Īt .util.ViewUtils$2.run(ViewUtils.java:153)Īt .dispatch(InvocationEvent.java:311)Īt (EventQueue.java:756)Īt $500(EventQueue.java:97)Īt $3.run(EventQueue.java:709)Īt $3.run(EventQueue.java:703)Īt (Native Method)Īt $JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)Īt (EventQueue.java:726)Īt (EventDispatchThread.java:201)Īt (EventDispatchThread.java:116)Īt (EventDispatchThread.java:105)Īt (EventDispatchThread.java:101)Īt (EventDispatchThread.java:93)Īt (EventDispatchThread.java:82) "KNIME Memory Alert Distributor" Id=86 WAITING on (Native Method) "Worker-14" Id=98 TIMED_WAITING on (Native Method) ![]() "Worker-16" Id=100 TIMED_WAITING on (Native Method) "OutPortView-Updater-3" Id=101 TIMED_WAITING on (Native Method) "Worker-17" Id=102 TIMED_WAITING on (Native Method) waiting on .LockSupport.parkNanos(LockSupport.java:215)Īt $TransferStack.awaitFulfill(SynchronousQueue.java:460)Īt $ansfer(SynchronousQueue.java:362)Īt .poll(SynchronousQueue.java:941)Īt .getTask(ThreadPoolExecutor.java:1066)Īt .runWorker(ThreadPoolExecutor.java:1127)Īt $n(ThreadPoolExecutor.java:617) 11:57:38,362 : DEBUG : pool-2-thread-1 : KNIMEApplication$4 : : : "KNIME-TableIO-2" Id=103 TIMED_WAITING on (Native Method) Full thread dump will follow as debug ouput. 11:57:38,362 : WARN : pool-2-thread-1 : KNIMEApplication$4 : : : Potential deadlock in AWT Event Queue detected. Very often KNIME gives a deadlock error and freezes, and most of the times I have to kill the process from the task manager - at the bottom you'll find the trace taken from the log file after it recovered by itself.ĭo you have any clue on what's happening? 7.I am working on KNIME 3.2.1 with 16G heap space, manipulating a matrix containing 300 rows and 125000 columns. The Java 8 documentation correctly calls the implementation lock-free. ![]() An interesting side-note here is that the Java documentation states that it's a wait-free queue, where it's actually lock-free. It's an implementation of the lock-free queue from M. Java already provides an implementation of a non-blocking queue, the ConcurrentLinkedQueue. The CAS operation ensures that we move the current head only if no other node has been removed in the meantime. The following code snippet outlines how CAS works: volatile int value īoolean cas(int expectedValue, int newValue) while(!pareAndSet(currentHead, nextNode)) Īgain, the essential part to pay attention to is the highlighted line. The important thing here is that CAS does not acquire a lock on the data structure but returns true if the update was successful, otherwise it returns false. Later on we'll see how the compare-and-swap operation achieves non-blocking access. However, what can happen is that if Thread 2 (or other threads) access the data structure with high frequency, then Thread 1 needs a large number of attempts until it finally succeeds. The advantage of this approach is that we don't need a lock. Thread 1 will then try again until it succeeds to complete the operation (green). Thread 1 attempts to access the data structure at the same time, detects the concurrent access, and returns immediately, informing the thread that it could not complete (red) the operation. Here, Thread 2 accesses the data structure but does not acquire a lock. The next picture illustrates thread starvation: If we suspend Thread 2 while it holds the lock, Thread 1 will have to wait forever. When Thread 1 attempts to acquire a lock as well, it needs to wait until Thread 2 releases the lock it won't proceed before it can get the lock. In the above picture, Thread 2 acquires a lock on the data structure.
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