Another chapter of my gc woes...
After somehow managing to reduce my weak ref processing problems (by using IMS and incremental CMS) I'm hitting rescan pauses. It seems that if CMS is running while some more memory is allocated/modified, rescan pause goes over the roof. Problem is that CMS is now running almost continiously due to incremental CMS and there are some places where we have to allocate 100-200MB of semi persistent data over period of minute or two (which is not so bad case IMHO - we are talking about few MB per second). When it happens, we get a quite large rescan pause. Is there any way to avoid this ? Put some more work to be done in concurrent mode ? (we have quite considerable buffer of free memory on top of our server needs so we can accept CMS rescanning stuff concurrently for a longer time without freeing memory, as long as it is not taking so big rescan pauses).
Mandatory gc output follows
(cardTable: 446 cards, re-scanned 52114 cards, 2 iterations)
[1 iterations, 0 waits, 52114 cards)] 30401.844: [CMS-concurrent-abortable-preclean: 0.641/20.023 secs]
(CMS-concurrent-abortable-preclean yielded 3 times)
30401.857: [GC[YG occupancy: 11343 K (24576 K)]30401.857: [Rescan (parallel) Finished root rescan work in 2th thread: 0.011 sec
Finished root rescan work in 1th thread: 0.012 sec
Finished root rescan work in 3th thread: 0.017 sec
Finished root rescan work in 0th thread: 0.056 sec
Finished dirty card rescan work in 3th thread: 1.013 sec
Finished dirty card rescan work in 2th thread: 1.400 sec
Finished dirty card rescan work in 0th thread: 1.405 sec
Finished dirty card rescan work in 1th thread: 2.049 sec
Finished work stealing in 1th thread: 0.000 sec
Finished work stealing in 3th thread: 1.032 sec
Finished work stealing in 0th thread: 0.600 sec
Finished work stealing in 2th thread: 0.651 sec
, 2.0621770 secs]30403.919: [weak refs processing, 0.0035454 secs]30403.923: [class unloading, 0.1012155 secs]30404.024: [scrub sy
mbol & string tables, 0.0123691 secs] [1 CMS-remark: 515043K(2068480K)] 526387K(2093056K), 2.2264839 secs]