[concurrency-interest] changing thread priority on the fly todeschedule zombie thread stuck in socketWrite0

David Holmes davidcholmes at aapt.net.au
Wed Jul 9 05:01:23 EDT 2014


Andy,

Java thread priorities have almost no meaning under normal scheduling
semantics. And on Linux (and elsewhere) changing Java Thread priority has no
affect on the native thread priority, by default.

David
  -----Original Message-----
  From: concurrency-interest-bounces at cs.oswego.edu
[mailto:concurrency-interest-bounces at cs.oswego.edu]On Behalf Of Andy Nuss
  Sent: Wednesday, 9 July 2014 1:36 AM
  To: concurrency-interest at cs.oswego.edu
  Subject: [concurrency-interest] changing thread priority on the fly
todeschedule zombie thread stuck in socketWrite0


  Hi,


  I'm in the early stage of figuring out why my massive parallelization of
S3 SDK usage for storing blobs causes a small percent of my amazon blob puts
to loop forever in socketWrite0 without completing due to packet flow
control problems with amazon server in the native socket write (sometimes
read as well).  Stopping in eclipse debugger and suspending and reactivating
such a thread proved to me it is looping in the native call, eating cpu and
never finishing.


  Though I haven't figured out yet why I'm the only one with this problem
with S3 and java, I was wondering if given that interrupting the thread does
not abort the native call at all, perhaps I could set the thread to the
minimum java thread priority, effectively causing it to starve relative to
all other threads in my program, and of course I would replace that zombie
thread in the pool.  Deploying on Linux.  Using JDK7.



  Andy
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