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
