Safepointing & Locking issue
Y. S. Ramakrishna
y.s.ramakrishna at oracle.com
Thu Jul 8 10:03:46 PDT 2010
On 07/08/10 08:06, Karen Kinnear wrote:
> It would also be very helpful if you could possibly gather information
> to determine
> why you are running so many safepoints.
> Could you possibly try running with the following flags on a fairly
> current jdk7 binary?
> -XX:+PrintSafepointStatistics -XX:+TraceSafepointCleanupTime
> That should tell you why you are running so many safepoints (which would
> not be caused
> by lock inflation/deflation). It will also tell you details of time
> spent in different components
> of the safepoint cleanup time, including lock deflation. Note that the
> flags require a development
> build, like fastdebug.
The two you mention above are also available in product builds, thanks to Xiaobin.
But probably moot now considering what Nicolas has figured out since the
first email on this thread (i.e. frequency of safepoints, not their
duration or deflation per se, being the cause of his overhead).
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