RFR: JDK-8078904 : CMS: Assert failed: Ctl pt invariant

Tom Benson tom.benson at oracle.com
Thu Aug 6 15:40:46 UTC 2015


Hi Eric,
I understand the comment below resulting in no longer preventing 
max_plab_samples from getting smaller than 2k.  But I see the factor of 
2 in computing _survivor_chunk_capacity and array size was also removed, 
which would have affected any size.  Was that just viewed as an 
arbitrary inflation, or ?
Tnx,
Tom

On 8/6/2015 9:28 AM, Eric Caspole wrote:
> Thomas and I had a IM about this the other day and in the end decided 
> to allow the main rescan chunk array to grow if the user explicitly 
> sets a very small MinTLABSize on the command line. There doesn't seem 
> to be any good reason to set a very small MinTLABSize except maybe 
> stress testing, and so it is simpler to grow this structure for that 
> unusual case rather than use the stride I had in v03.
>
> The new one is here:
>
>  http://cr.openjdk.java.net/~ecaspole/JDK-8078904/04/webrev/
>
> Bug:
>  https://bugs.openjdk.java.net/browse/JDK-8078904
>
> I tested this with the failing example using many combinations of gc
> thread counts and many MinTLABSize values from 64 up to 4M. And JPRT.
> Thanks,
> Eric



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