Growing GC Young Gen Times

[wmadams824 at comcast.net]

Hi, Matt: 


I don't have a solution but I can add more information, as I recently dealt with the same issue. My customer's app also generated a large amount of garbage per unit time. We were using CMS (with most of the same options you are using, but a smaller heap) and saw the same behavior of the young GC time increasing monotonically. Some additional information: their app did experience a number of CMS collections per day, and the young-GC collection time still continued to rise. We also arranged for a Full GC to occur in the middle of the night (to see if fragmentation in the old generation was impacting young-GC collection times), and still saw no change in the ever-increasing time for young GC. Printing FLS stats at level 2 showed no noticeable fragmentation in the old or perm gens. The only thing that caused the young GC times to go down was to bounce the JVM (at which point they began rising again, of course). 


While I was there, the server ran for a max of 3 or 4 days between bounces, and the young-GC collection time never leveled off. At least that's where they were when they threw me out of the office. :) 


Regards, Wayne 

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