JDK-8171119: Low-Overhead Heap Profiling

[Robbin Ehn]

Hi JC,

On 01/30/2018 04:22 AM, JC Beyler wrote:
> - Collectedheap still needs to call AllocTracer to see if it is to be
> sampled, I can't hide everything in it without a bigger refactor (want
> me to try?)

Yes we need a bigger refactor to do this nicely.
I suggested not doing that now, so just rollback to the previously version.

Thanks for having a look at it!

/Robbin

> 
> On Mon, Jan 29, 2018 at 1:29 AM, Robbin Ehn <robbin.ehn at oracle.com> wrote:
>> Hi JC, thanks!
>>
>> I'm happy with current state, looks good!
>>
>> Truncated:
>>
>> On 01/27/2018 05:01 AM, JC Beyler wrote:
>>>
>>> This is strange but I'm assuming it is because we are not working on
>>> the same repo?
>>>
>>> I used:
>>> hg clone http://hg.openjdk.java.net/jdk/hs jdkhs-heap
>>>
>>> I'll try a new clone on Monday and see. My new version moved hard_end
>>> back to public so it should work now.
>>
>>
>> Sorry this compile error was in closed code.
>> Now the closed part compiles, thanks.
>>
>>>
>>> Fair enough, hopefully Thomas will chime in. Are you saying that this
>>> first version could go in and we can work on a refinement? Or are you
>>> saying I should work on this now at the same time and fix it before
>>> this V1 goes in? (Just so I know :))
>>
>>
>> We may have to change this before integration, but for now keep it as is.
>>
>>> I'll look at this on Monday then!
>>
>>
>> Great!
>>
>> /Robbin
>>
>>
>>>
>>> Thanks for the reply and have a great weekend!
>>> Jc
>>>
>>>>
>>>>>
>>>>>> ####
>>>>>> Minor nit, when declaring pointer there is a little mix of having the
>>>>>> pointer adjacent by type name and data name. (Most hotspot code is by
>>>>>> type
>>>>>> name)
>>>>>> E.g.
>>>>>> heapMonitoring.cpp:711     jvmtiStackTrace *trace = ....
>>>>>> heapMonitoring.cpp:733         Method* m = vfst.method();
>>>>>> (not just this file)
>>>>>>
>>>>>
>>>>> Done!
>>>>>
>>>>>> ####
>>>>>> HeapMonitorThreadOnOffTest.java:77
>>>>>> I would make g_tmp volatile, otherwise the assignment in loop may
>>>>>> theoretical be skipped.
>>>>>>
>>>>>
>>>>> Also done!
>>>>
>>>>
>>>>
>>>> Looks good, thanks!
>>>>
>>>> /Robbin
>>>>
>>>>>
>>>>> Thanks again!
>>>>> Jc
>>>>>
>>>>
>>