RFR (M): 8014659: NPG: performance counters for compressed klass space

Christian Tornqvist christian.tornqvist at oracle.com
Thu Aug 15 13:34:51 UTC 2013

Hi Erik,

First of all, I've only reviewed the test part of this change. Please add a
small test for the Asserts class, this would make it a lot easier to
fix/change it in the future. Otherwise I think the change looks good, thanks
for adding Asserts and the other classes to testlibrary collection :)


-----Original Message-----
From: hotspot-runtime-dev-bounces at openjdk.java.net
[mailto:hotspot-runtime-dev-bounces at openjdk.java.net] On Behalf Of Erik
Sent: Wednesday, August 14, 2013 10:49 AM
To: hotspot-gc-dev at openjdk.java.net; hotspot-runtime-dev at openjdk.java.net
Subject: RFR (M): 8014659: NPG: performance counters for compressed klass

Hi all,

this change adds performance counters for compressed class space.


Changes to hotspot:
The main changes are in metaspaceCounters.hpp and metaspaceCounters.cpp,
where the class MetaspaceCounters has been split up into MetaspaceCounters
and MetaspacePerfCounters. MetaspaceCounters now owns an instance of
MetaspacePerfCounters. The class CompressedClassSpaceCounters has been added
which also has its own instance of MetaspacePerfCounters.
MetaspacePerfCounters initializes and updates the actual performance

The changes in metaspace.hpp/cpp were needed to get some additional data
from the metaspace data structures. The method
free_chunks_in_total(mdtype) was made public and the method
free_bytes(mdtype) was added. Some common functionality was extracted into
get_space_list(mdtype) which got rid of some duplicated code.

The changes in:
- g1MonitorinSupport.cpp
- parallelScavengeHeap.cpp
- genCollectedHeap.cpp
- universe.cpp
are only "one-liners" that either update or initialize the new performance

Changes to the testlibrary:
- Added Asserts.java for writing asserts like "assertTrue",
  "assertEquals", etc.
- Added PerfCounter.java and PerfCounters.java to make it easy to
  inspect performance counters for the currently running VM.
- Added InputArguments.java so a test can check the arguments it got
- Added InMemoryJavaCompiler.java for compiling a string into bytecode.
  Useful for loading classes generated at runtime without using files.
- Added ByteCodeLoader.java for defining a new class when you already
  have the bytecode.

- Added the new test TestMetaspacePerfCounters.java



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