RFR 8075926: Add a sun.management.JMXConnectorServer perf counter to track its state

[Jaroslav Bachorik]

On 18.5.2015 10:41, Staffan Larsen wrote:
>
>> On 18 maj 2015, at 10:25, Jaroslav Bachorik <jaroslav.bachorik at oracle.com> wrote:
>>
>> On 18.5.2015 10:21, Staffan Larsen wrote:
>>> Looks good, but why is the reverseBytes needed?
>>>
>>> 60             this.bb.asLongBuffer().put(Long.reverseBytes(l));
>>
>> For some reason Perf.createLong(...) will create bytebuffer with the HILO byte order reversed when compared to how long is usually represented.
>
> I think you should set the order() of the ByteBuffer before you create the LongBuffer. See the code in sun.misc.PerfCounter:
>
> private PerfCounter(String name, int type) {
>      this.name = name;
>      ByteBuffer bb = perf.createLong(name, type, U_None, 0L);
>      bb.order(ByteOrder.nativeOrder());
>      this.lb = bb.asLongBuffer();
> }

Done. Please, see 
http://cr.openjdk.java.net/~jbachorik/8075926/webrev.01 for the updated 
webrev.

-JB-

>
> /Staffan
>
>>
>> -JB-
>>
>>>
>>> Thanks,
>>> /Staffan
>>>
>>>> On 13 maj 2015, at 17:39, Jaroslav Bachorik <jaroslav.bachorik at oracle.com> wrote:
>>>>
>>>> Please, review the following change
>>>>
>>>> Issue : https://bugs.openjdk.java.net/browse/JDK-8075926
>>>> Webrev: http://cr.openjdk.java.net/~jbachorik/8075926/webrev.00
>>>>
>>>> The sun.management.JMXConnectorServer.<version>.<key> perf counters are not updated when the remote management agent is stopped.
>>>>
>>>> The perf counters show stale data and mislead the users.
>>>>
>>>> Since it is not possible to 'un-export' perf counters we need an additional counter tracking the version of the related perf counters in use.
>>>>
>>>> In the current implementation each start of the remote management agent will export a new set of the related perf counters (sun.management.JMXConnectorServer.<version>.<key>) with the <version> part increased by one. The first remote management agent start will use 0 as its version.
>>>>
>>>> The new counter 'sun.management.JMXConnectorServer.remote' will have value of -1 if the remote management is stopped and non-negative number corresponding to the version of the related perf counters in use.
>>>>
>>>> Thanks,
>>>>
>>>> -JB-
>>>
>>
>