Request for Review (M) - 6858051: Create GC worker threads dynamically

Jon Masamitsu jon.masamitsu at
Wed Apr 27 15:21:22 UTC 2016

I updated my repository and redid the webrev.   The patch applied cleanly
so I don't expect you'll notice much difference from the first but if you
haven't started, start here.

On 04/26/2016 10:06 PM, Jon Masamitsu wrote:
> 6858051: Create GC worker threads dynamically
> This change creates a minimal number of GC workers at JVM initialization
> and then adds additional workers as they are needed.  This has been 
> made part of the
> UseDynamicNumberOfGCThreads feature.  When a parallel task is about to
> be executed, the number of workers needed to execute the task is 
> calculated (call
> that number N).  If that number of workers already exist, then no 
> additional workers
> are created.  If fewer than N exists, then additional workers are 
> created.  Workers
> are not destroyed if not needed for the task.
> The UseParallelGC way of executing parallel tasks is different from 
> the other
> collectors so it has a somewhat separate implementation.
> Testing: gc_test_suite with and without UseDynamicNumberOfGCThreads.
> Performance testing with the prototype did not show any regression with
> UseDynamicNumberOfGCThreads turned on.     RBT testing for hotspot_gc
> is in progress.
> Thanks.
> Jon

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