Jvm asserts with DynamicNumberOfGCThreads and ParallelRefProcEnabled

[Lindenmaier, Goetz]

Hi Jon and Thomas 

Thanks for taking care of this issue!

Best regards,
  Goetz

> -----Original Message-----
> From: hotspot-gc-dev [mailto:hotspot-gc-dev-bounces at openjdk.java.net]
> On Behalf Of Jon Masamitsu
> Sent: Montag, 8. Februar 2016 20:07
> To: hotspot-gc-dev at openjdk.java.net
> Subject: Re: Jvm asserts with DynamicNumberOfGCThreads and
> ParallelRefProcEnabled
> 
> 
> Thomas,
> 
> Thanks for filing the CR.  I assigned it to myself.
> 
> Jon
> 
> On 02/08/2016 02:29 AM, Thomas Schatzl wrote:
> > Hi Goetz,
> >
> > On Mon, 2016-02-08 at 07:26 +0000, Lindenmaier, Goetz wrote:
> >> Hi,
> >>
> >> We have ParallelRefProcEnabled enabled. I found that
> >> TestDynamicNumberOfGCThreads.java
> >> is asserting because of that.
> >>
> >> The following command line runs into
> >> g1CollectedHeap, process_discovered_references(), assert(rp->num_q()
> >> == no_of_gc_workers) :
> >> -XX:+ParallelRefProcEnabled -XX:+UseG1GC -Xmx10M
> >> -XX:+UseDynamicNumberOfGCThreads -Xlog:gc+task=trace
> >> TestDynamicNumberOfGCThreads$GCTest
> >>
> >> On my machine, there are 33 queues,  but only 2 processing threads.
> >> I think this either should be fixed, or the combination of flags
> >> should be avoided by ergonomics.
> >>
> >> Also, the test should be extended by that command line, I guess.
> >    filed JDK-8149343. Thanks for reporting this issue.
> >
> > Thanks,
> >    Thomas
> >