JDK-8087107 : Expose code cache statistics via perfdata counters
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 8,9,10
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • OS: generic
  • CPU: generic
  • Submitted: 2015-06-10
  • Updated: 2019-01-15
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tbdUnresolved
Related Reports
Relates :  
JDK-8198691 - CodeHeap State Analytics
Description
The size of the code cache, its usage and the activity of the code cache sweeper would be useful information to export and track via perf data counters.

I am attaching a patch (based on jdk 8uXX version of hotspot) which exposes a few new counters, viz, the top few lines in the display below:

$ jcmd <pid> PerfCounter.print | grep -i "sun\.ci\."
sun.ci.codeCacheCapacity=6291456
sun.ci.codeCacheMaxCapacity=6291456
sun.ci.codeCacheMethodsReclaimedNum=1030
sun.ci.codeCacheSweepsTotalNum=93
sun.ci.codeCacheSweepsTotalTimeMillis=63
sun.ci.codeCacheUsed=3386880
...


These counters are useful to quickly assess code cache churn and sweeper activity.
Comments
I'm in favor of adding more code cache data to the perfdata counters. * The current patch is missing tests. * It would be good if terminology and data points were aligned between the trace events (trace.xml) and the perfdata counters.
15-06-2015
JVM stat stuff is worked on by both Runtime and Serviceability teams. The counters themselves are for the code cache which is the Compiler team. Moving to hotspot/compiler for now.
10-06-2015
codecache.patch attached (as in description).
10-06-2015