RFR: 8078901: Add trace event for G1 MMU information

Marcus Larsson marcus.larsson at oracle.com
Tue Jun 30 13:12:51 UTC 2015


Hi,

On 06/30/2015 01:32 PM, Stefan Johansson wrote:
> I need one more reviewer before pushing.
>
> Webrev with latest updates:
> http://cr.openjdk.java.net/~sjohanss/8078901/hotspot.02/
>

Looks good to me.

Thanks,
Marcus

> Stefan
>
> On 2015-06-30 13:14, Stefan Johansson wrote:
>> Thanks Erik!
>>
>> Stefan
>>
>> On 2015-06-30 10:58, Erik Helin wrote:
>>> On 2015-06-26, Stefan Johansson wrote:
>>>> Thanks Erik for looking at this,
>>>>
>>>> On 2015-06-18 10:44, Erik Helin wrote:
>>>>> Hi Stefan,
>>>>>
>>>>> sorry for not getting to this earlier, thanks a lot for this patch!
>>>>>
>>>>> On 2015-04-30, Stefan Johansson wrote:
>>>>>> Hi,
>>>>>>
>>>>>> Please review this change to add a trace event for MMU tracking:
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8078901
>>>>>>
>>>>>> Webrev:
>>>>>> http://cr.openjdk.java.net/~sjohanss/8078901/hotspot.00/
>>>>> I have two comments:
>>>>> - instead of using multiple inheritance, can you instead have the
>>>>>    G1MMUTracer as a field in G1NewTracer and G1OldTracer? Then you 
>>>>> can
>>>>>    have a getter to the field.
>>>>> - in G1MMUTracer, can you have the function report_mmu not take a
>>>>>    G1MMUTracker* but instead have two additional double 
>>>>> parameters, one
>>>>>    for time_slice and one for max_gc_time? This way the tracers don't
>>>>>    need to know about G1MMUTracker.
>>>> Erik and I have discussed this a little more off-line and come to the
>>>> conclusion to have an all-static class handling the the reporting 
>>>> of the MMU
>>>> event. This avoids the multiple inheritance and other problems of 
>>>> having a
>>>> G1MMUTracer as part of the other tracers. This solution slightly 
>>>> differ from
>>>> previously uses of the "tracers" but still keeps the code separated 
>>>> in a
>>>> good way.
>>>>
>>>> New webrev:
>>>> http://cr.openjdk.java.net/~sjohanss/8078901/hotspot.01/
>>> Looks good, Reviewed. As we discussed offline, please revert the 
>>> changes
>>> touching G1OldTracer and CMSTracer (no need to re-review that change).
>>>
>>> Thanks,
>>> Erik
>>>
>>>> Thanks,
>>>> Stefan
>>>>> Thanks!
>>>>> Erik
>>>>>
>>>>>> Summary:
>>>>>> When adding pause information to the G1MMUTracker, it now reports a
>>>>>> trace-event with the latest MMU information.
>>>>>>
>>>>>> add_pause() previously took a bool argument that was unused, but 
>>>>>> said
>>>>>> whether or not it was a concurrent-cycle pause. I removed the 
>>>>>> bool argument
>>>>>> and added G1MMUTracer* argument. The G1MMUTracer is an interface 
>>>>>> that both
>>>>>> the stw-tracer and the cm-tracer now implement to make sure the 
>>>>>> correct GC
>>>>>> id is provided with the event.
>>>>>>
>>>>>> Thanks,
>>>>>> Stefan
>>
>



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