Review Request for 6878481: Add performance counters in the JDK

[Mandy Chung]

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.

I added /usepmtimer  in boot.ini on my system (thanks David for the 
suggestion).  The performance run shows insignificant perf impact.

Windows XP SP 3 Intel Core 2 CPU @3.0Ghz, 1.96 GB RAM

==============================================================================
mchung.baseline.server:
   Benchmark           Samples        Mean     Stdev             Geomean 
Weight
   reference_server         20     7615.99    123.75
     jetstream              20      131.78     29.37             0.10
     scimark                20      618.00      6.35             0.15
     specjbb2000            20    93732.74    540.37             0.15
     specjbb2005            20    43062.47    182.61             0.25
     specjvm98              20      575.46      1.94             0.15
     volano25               20    46464.90   1164.30             0.20
==============================================================================
mchung.perfcounters:
   Benchmark           Samples        Mean     Stdev   %Diff     P 
Significant
   reference_server         20     7575.65     34.80   -0.53 0.174 
       *
     jetstream              20      124.67      1.88   -5.40 0.293 
       *
     scimark                20      619.47      5.19    0.24 0.426 
       *
     specjbb2000            20    93573.49    663.77   -0.17 0.411 
       *
     specjbb2005            20    43095.83    190.47    0.08 0.575 
       *
     specjvm98              20      576.44      3.05    0.17 0.233 
       *
     volano25               20    46064.85   1034.46   -0.86 0.258 
       *
==============================================================================
   * - Not Significant: A non-zero %Diff for the mean could be noise. If the
       %Diff is 0, an actual difference may still exist. In either case, 
more
       samples would be needed to detect an actual difference in sample 
means.

Thanks
Mandy

Mandy Chung wrote:
> This is related to 6857194: Add hotspot new perf counters to aid class 
> loading performance measurement.
> 
> It's useful to add performance counters in the library code so that perf 
> data from the JDK and VM can be collected and output in a unified way 
> (written in the jvmstat shared memory buffer).  I add a simple 
> sun.misc.PerfCounter class to maintain the list of perf counters for the 
> library to use.  This fix only instruments the class loading and jar/zip 
> to collect simple basic metrics.   Additional perf counters will be 
> added in the future.
> 
> Webrev:
>     http://cr.openjdk.java.net/~mchung/6878481/webrev.00/
> 
> Thanks
> Mandy