Review Request for 6878481: Add performance counters in the JDK

[Alan Bateman]

Mandy Chung wrote:
> Alan, David, Remi, Iris,
>
> Thanks for the review and the revised webrev at:
>     http://cr.openjdk.java.net/~mchung/6878481/webrev.01/
>
> I incorporate the comments you have and minimize the number of 
> System.nanoTime() calls and also remove the number of opened jars perf 
> counters.  Please let me know if you have further comments.
This looks much better, in particular the overhead in ClassLoader is 
much reduced. Also, I see you've removed the special counter for JAR 
files, which make sense.

Minor nit but I assume you can initialize perf as:
  private static final Perf perf =
     AccessController.doPrivileged(new Perf.GetPerfAction());

Also minor nit: in the javadoc of the PerfCounter's public methods - I 
assume you meant to use /** instead of /*.

Method naming is hard (and often subjective) but there are updates like 
this:
  PerfCounter.getParentDelegationTime.inc(t1 - t0);
which might be easier to read as:
  PerfCounter.getParentDelegationCounter().addTime(t1 - t0)

Also:
  PerfCounter.getZipFileCount().inc();
which might be cleaer as:
  PerfCounter.getZipFileCounter().increment();

Just a suggestion of course. Otherwise, looks okay to me and I'm looking 
forward to seeing the output once these changes are in.

-Alan.