concurrent mode failure in minor gc/ -XX:CMSFullGCsBeforeCompaction=1

Y.S.Ramakrishna at Sun.COM Y.S.Ramakrishna at Sun.COM
Mon Apr 27 09:13:48 PDT 2009


What Jon said re contacting Sun support etc.

One important thing we have learned about CMS is
that the filtering of short-lived objects in the young gen is
important both for relieving short-term pressure on the CMS collector
and in the long-term for reducing fragmentation of the old
gen, either or both of which might otherwise cause concurrent mode failure.

I have never myself found CMSFullGCsBeforeCompaction != 0 to be particularly useful
as a tuning knob.

regards.
-- ramki

>> 1)
>>
>> Options used :
>> -server -Xmx768m -Xms768m -XX:MaxNewSize=256m -XX:NewSize=256m
>> -XX:+UseParNewGC -XX:+CMSParallelRemarkEnabled -XX:+UseConcMarkSweepGC
>> -XX:CMSInitiatingOccupancyFraction=60 -XX:+UseCMSInitiatingOccupancyOnly
>>
...
>>
>> 2)
>>
>> Options used:
>> -server -Xmx768m -Xms768m -XX:MaxNewSize=256m -XX:NewSize=256m
>> -XX:+UseParNewGC -XX:+CMSParallelRemarkEnabled -XX:+UseConcMarkSweepGC
>> -XX:CMSInitiatingOccupancyFraction=60
>> -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSFullGCsBeforeCompaction=1
>>
...
> 
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