CMS collection keep working during holiday dragonken at
Sun Oct 5 17:38:30 UTC 2008

Anyone help? Someone has exactly same case to me and he posted the case at
Jon Masamitsu's blog:

Trying the new CMS in 1.6 and it seems to work nicely for a while but then
it starts kicking out these CMS aborts. I can find nothing anywhere talking
about what is happening. This happens over and over until a full GC happens.
>From what I can tell the CMS collector never completes and is therefore not
doing anything except taking CPU time. CMS: abort preclean due to time
407.606: [CMS-concurrent-abortable-preclean: 0.149/5.058 secs]

The CMS will be triggered by -XX:CMSInitiatingOccupancyFraction=70 but it
seems that it has no effect but continue keeping CMS until a Full GC (caused
by 'concurrent mode failure'). In my case, it always happen in non-busy
hours but the CMS behave normally in busy / peak hours.

I think it is not related to 'cms abort preclean' but it's really taking CPU
time but do nothing (around 4 hours) and it has chance to have a big GC when
the old-gen is full.

Best Regards,

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