High Reference Processing/Object Copy time

Thomas Schatzl thomas.schatzl at oracle.com
Thu Jul 13 08:06:34 UTC 2017


On Thu, 2017-07-13 at 04:58 +0000, Bernd Eckenfels wrote:
> The sys time is very high in this snippet, how to the other snippets
> compare? Did you turn off transparent huge pages (THP) in your OS and
> is there no swapping happening?

The documentation offers some more potential issues when there is high
system time: https://docs.oracle.com/javase/9/gctuning/garbage-first-ga
rbage-collector-tuning.htm#GUID-8D9B2530-E370-4B8B-8ADD-A43674FC6658 (T
he section is applicable to both JDK8 and 9).

The VM/garbage collector is a user level program. High system time (at
least as high as in your snippet) strongly indicates a problem in the
environment (or in the interaction with your environment, i.e. memory
or I/O related).

> BTW: this is more a discussion for the user mailing list.

Agree, please move to the hotspot-gc-use list which is more


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