Full Java memory metrics

Questions about YourKit Java Profiler
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Loïc LAMBERT
Posts: 17
Joined: Mon Jul 18, 2005 8:21 am

Full Java memory metrics

Post by Loïc LAMBERT »

Thanks to yourkit, I have fixed a few tricky object reference leaks.
But still, the memory of the application is raising over time. It happens under XP and Linux, so it's related to Java, not the operating system. The process size increase, but the metrics of the heap and non heap memory are stable, far under the max heap memory set.
The question is: what is increasing ?
- DirectBuffers
- some internal memory : strings, thread local memory, GC internal buffers?
- native allocation (mission impossible?)

It would be fine to have metrics on that too, to know what's going wrong.
This info may be JVM-dependent, but I tested a few ones and they seems to all include some Sun internal classes, so that may help to make some "generic stuff".

We have 4 ThreadLocal variables, and one is missing in the memory snapshot (the most in use). Maybe it hides because it feels guilty ;-)
The last point is more a bug.

By the way, any idea on that issue would be welcome :-)

Loïc
rblasch
Posts: 64
Joined: Mon Jan 10, 2005 7:13 pm

Post by rblasch »

Check out the great article "Don't forget about memory" at
http://www-128.ibm.com/developerworks/l ... -memusage/.

Ron
Loïc LAMBERT
Posts: 17
Joined: Mon Jul 18, 2005 8:21 am

Post by Loïc LAMBERT »

Thanks Ron for that useful link. I knew some of these tools but not all, especially vadump.
We have some clues about our problem, it should be fixed soon.

About the feature: I still think that would be great to have information about DirectBuffer and String memory consumption, but it's more some new parameters to add in JVMPI.
Maybe the YourKit team would be able convince the Sun developers to add some metrics !

Regards,
Loïc
Vladimir Kondratyev
Posts: 1624
Joined: Tue Aug 10, 2004 7:52 pm

Post by Vladimir Kondratyev »

Loïc LAMBERT
Posts: 17
Joined: Mon Jul 18, 2005 8:21 am

Post by Loïc LAMBERT »

For those who are interested on the problem: we are one more victim of the terrible implementation of File.deleteOnExit() :(
See Sun bug parade: 4513817, 4813777, ...
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