Perfcounter are dynamic and can change. Applications must be aware of
that and work around it.
Perf counters being dynamic must be documented and must not be a
deterrent for consuming them (via Dymanic MBean).
Regards
Harsha
On Monday 27 February 2017 11:22 PM, Erik Gahlin wrote:
If somebody writes a tool that plots the values that the perf counters
provide, which is bound to happen if it is exposed via JMX, but then
the internals of the JVM is changed and the perf counter value is
removed or it is incorrect.
Erik
Hi Erik,
I am not sure if Perf Counters could be disabled. If yes, then
PerfCounter MBean must throw appropriate exception while getting
MBeanInfo.
I don't know about tests for PerfCounter. The webrev contains tests
for PerfCounter MBean.
I am not sure how we will be breaking other's code. Could you please
elaborate?
Thanks
Harsha
On Monday 27 February 2017 07:39 PM, Erik Gahlin wrote:
Hi Harsha,
How will perf counters be supported?
Can they be removed at anytime, or only at major releases etc. Do we
have tests for them? I think it would be good know, and perhaps
state somewhere so we don't break people's code.
Erik
Hi All,
Please review the below RFE,
JDK-8007141 <http://JDK-8007141> : Introduce Dynamic MBean exposing
the perf counters.
with webrev at,
http://cr.openjdk.java.net/~hb/8007141/webrev.00/
Appreciate if I can get inputs for below.
1. Location of HotSpotPerfCounterMBean. It is located at
src/jdk.management/share/classes/com/sun/management/internal. It
can be moved to src/jdk.management/share/classes/com/sun/management
if required.
2. Javadoc comments for HotSpotPerfCounterMBean. Not sure if it is
adequate.
3. Description for each attribute of MBean. I am using getUnits(),
getVariability(), and getFlags() for description. I am not sure if
that is the right description. Appreciate inputs from someone who
knows perf counters well.
Thanks
Harsha
