Perplexing GC Time Growth

[Y.S.Ramakrishna at Sun.COM]

Hi Jason --

Y.S.Ramakrishna at Sun.COM wrote:
...
> While we think of potential reasons for this, or mull over
> appropriate sensors that can lay bare the root cause here,
> could you, on a quick hunch, do a quick experiment and tell
> me if adding the options -XX:+CMSClassUnloadingEnabled makes
> any difference to the observations above. [Does your application
> do lots of class loading or reflection or string interning?]

I think i screwed up a bit here. I was assuming you were using
the (newest) OpenJDK build. As it happens, in 6u3 and older
you need to specify both +CMSClassUnloadingEnabled _and_
+CMSPermGenSweepingEnabled, else you do not get the desired effect.
Sorry this was fixed after 6u3, so the additional flag did not
do anything in your case.

Let me know if the additional flag (please use both) made
a difference, and apologies for the bad user interface here
(set right as of 6u4 and in OpenJDK).

-- ramki

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