[concurrency-interest] ForkJoinTask.externalAwaitDone() co-operates only with commonPool?

Doug Lea dl at cs.oswego.edu
Mon Feb 6 09:14:56 EST 2017


On 02/06/2017 01:47 AM, kirk at kodewerk.com wrote:
> Hi,
>
> A while back I sifted through f-j and sorted out a way to instrument
> it with JMX. I am sure that my hack wasn’t the best way to instrument
> f-j but it did give me the information I needed at the time. Given
> the importance of the common thread-pool and f-j I am wondering if it
> might be a good idea to explore a way to add instrumentation so that
> important metrics can be exposed via the Platform MBean server to
> improve observability in the runtime?
>

What metrics do you have in mind? Are they different than
what you can get by calling fjp.toString (which collects
up the status query methods)? Here's a sample output:

java.util.concurrent.ForkJoinPool at 2ef5e5e3[Running, parallelism = 64, 
size = 64, active = 0, running = 0, steals = 112778, tasks = 0, 
submissions = 0]

In general, rather than linking to JMX etc, j.u.c components
have status query methods summarized in toString methods, that
we hope are easy to connect to any monitoring facility.

-Doug



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