"Parking to wait for" just means the thread has been put to sleep while waiting for some synchronized resource. In this case, "ConditionObject" indicates it's probably await()ing on a condition variable. This almost always means that thread is just waiting for notification from another thread that there's something to do (AbstractQueuedSynchronizer is a generic low-level synchronization utility and used for things like BlockingQueues). The only way it would be hung in this condition is if no other thread will ever wake it up (e.g. due to some deadlock, the thread it relies on to wake it up dies, etc.)
With just the line given, you can't tell exactly what's going on, but brokers especially may use very little CPU since most of what they do is IO. Seeing these lines in a thread dump is completely normal since there will often be threads just waiting for new work to do, so they shouldn't worry you unless you have other reason to believe something is wrong. On Mon, Apr 13, 2015 at 9:19 PM, Sharma, Prashant <psha...@netsuite.com> wrote: > > Kafka version is 0.8.1.1. On taking a thread dump against one of our > servers in Kafka Cluster, i see lot of threads with message below: > > > > "SOMEID-9" id=67784 idx=0x75c tid=24485 prio=5 alive, parked, > native_blocked, daemon > > -- Parking to wait for: > java/util/concurrent/locks/AbstractQueuedSynchronizer$ConditionObject@0x100a13500 > > at jrockit/vm/Locks.park0(J)V(Native Method) > > > > There are multiple threads with the message “Parking to wait for” with the > same objectId- 0x100a13500. > > Does this imply that the consumer threads are stuck or just sitting > idle? > > Thanks, > > Prashant > > [image: Suite World 2015] <http://www.netsuite.com/suiteworld> > To learn more about SuiteWorld, visit http://www.netsuitesuiteworld.com/ > <http://www.netsuite.com/suiteworld> > > NOTICE: This email and any attachments may contain confidential and > proprietary information of NetSuite Inc. and is for the sole use of the > intended recipient for the stated purpose. Any improper use or distribution > is prohibited. If you are not the intended recipient, please notify the > sender; do not review, copy or distribute; and promptly delete or destroy > all transmitted information. Please note that all communications and > information transmitted through this email system may be monitored and > retained by NetSuite or its agents and that all incoming email is > automatically scanned by a third party spam and filtering service which may > result in deletion of a legitimate e-mail before it is read by the intended > recipient. > -- Thanks, Ewen
