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

[Staffan Larsen]

Looks good!

Thanks,
/Staffan

> On 18 maj 2015, at 19:23, Jaroslav Bachorik <jaroslav.bachorik at oracle.com> wrote:
> 
> 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-
>>>> 
>>> 
>> 
>