Uwe: Thanks for working with them to get all these issues fixed.

On Mon, Mar 11, 2013 at 7:34 PM, Uwe Schindler <u...@thetaphi.de> wrote:
> Hi,
>
> FYI, Oracle has a fix for the G1GC hang in UIMA waiting for review:
>
> Issue: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8009536
> Webrev: 
> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2013-March/006215.html
> Patch: http://cr.openjdk.java.net/~johnc/8009536/webrev.0/
>
> Thanks to John Cuthbertson and Bengt Rutisson @ Oracle for fixing so fast! We 
> just have to wait for a new JDK8 build with that fix included (and some more 
> for the other Lucene-related bugs).
> Uwe
>
> -----
> Uwe Schindler
> H.-H.-Meier-Allee 63, D-28213 Bremen
> http://www.thetaphi.de
> eMail: u...@thetaphi.de
>
>
>> -----Original Message-----
>> From: Mark Miller [mailto:markrmil...@gmail.com]
>> Sent: Wednesday, March 06, 2013 7:52 PM
>> To: dev@lucene.apache.org
>> Subject: Re: JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32 bit)
>>
>> Awesome work Uwe! Nice job getting this some attention.
>>
>> - mark
>>
>> On Mar 6, 2013, at 10:41 AM, Uwe Schindler <u...@thetaphi.de> wrote:
>>
>> > It seems that there is already an explanation from the Oracle engineer:
>> >
>> >> -----Original Message-----
>> >> From: John Cuthbertson [mailto:john.cuthbert...@oracle.com]
>> >> Sent: Wednesday, March 06, 2013 7:04 PM
>> >> To: Thomas Schatzl
>> >> Cc: Uwe Schindler; hotspot-gc-...@openjdk.java.net; 'David Holmes';
>> >> 'Dawid Weiss'; hotspot-...@openjdk.java.net
>> >> Subject: Re: JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32
>> >> bit)
>> >>
>> >> Hi Everyone,
>> >>
>> >> All:
>> >> I've looked at the bug report (haven't tried to reproduce it yet) and
>> >> Bengt's analysis is correct. The concurrent mark thread is entering
>> >> the synchronization protocol in a marking step call. That code is
>> >> waiting for some non-existent workers to terminate before proceeding.
>> >> Normally we shouldn't be entering that code but I think we overflowed
>> >> the global marking stack (I updated the CR at ~1am my time with that
>> >> conjecture). I think I missed a set_phase() call to tell the parallel
>> >> terminator that we only have one thread and it's picking up the
>> >> number of workers that executed the remark parallel task.
>> >>
>> >> Thomas: you were on the right track with your comment about the
>> >> marking stack size.
>> >>
>> >> David:
>> >> Thanks for helping out here. The stack trace you mentioned was for
>> >> one the refinement threads - a concurrent GC thread. When a
>> >> concurrent GC thread "joins" the suspendible thread set, it means
>> >> that it will observe and participate in safepoint operations, i.e.
>> >> the thread will notice that it should reach a safepoint and the safepoint
>> synchronizer code will wait for it to block.
>> >> When we wish a concurrent GC thread to not observe safepoints, that
>> >> thread leaves the suspendible thread set. I think the name could be a
>> >> bit better and Tony, before he left, had a change that used a scoped
>> >> object to join and leave the STS that hasn't been integrated yet.
>> >> IIRC Tony wasn't happy with the name he chose for that also.
>> >>
>> >> Uwe:
>> >> Thanks for bringing this up and my apologies for not replying sooner.
>> >> I will have a fix fairly soon. If I'm correct about it being caused
>> >> by overflowing the marking stack you can work around the issue by
>> >> increasing the MarkStackSize.you could try increasing it to 2M or 4M
>> >> entries (which is the current max size).
>> >>
>> >> Cheers,
>> >>
>> >> JohnC
>> >
>> > -----
>> > Uwe Schindler
>> > H.-H.-Meier-Allee 63, D-28213 Bremen
>> > http://www.thetaphi.de
>> > eMail: u...@thetaphi.de
>> >
>> >
>> >> -----Original Message-----
>> >> From: Uwe Schindler [mailto:u...@thetaphi.de]
>> >> Sent: Wednesday, March 06, 2013 1:35 PM
>> >> To: dev@lucene.apache.org
>> >> Subject: FW: JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32
>> >> bit)
>> >>
>> >> They already understood the G1GC problem with JDK 8 b78/b79 and
>> >> working on a fix. This was really fast:
>> >> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2013-
>> >> March/006128.html
>> >>
>> >> Uwe
>> >>
>> >> -----
>> >> Uwe Schindler
>> >> H.-H.-Meier-Allee 63, D-28213 Bremen
>> >> http://www.thetaphi.de
>> >> eMail: u...@thetaphi.de
>> >>
>> >
>> >
>> >
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>>
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