RFR - [RFE] JDK-8007141 : Introduce Dynamic MBean exposing the perf counters

[Erik Gahlin]

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
>>>
>>>
>>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/serviceability-dev/attachments/20170227/6a0f21ab/attachment.html>