RFR (L): 8149374: Replace C1-specific collection classes with universal collection classes

[Filipp Zhinkin]

Here is an webrev updated according Mikael's comments:

http://cr.openjdk.java.net/~fzhinkin/8149374/webrev.02/

Tested using hotspot_all tests w/ CMS turned on.

Thanks,
Filipp.

On Fri, Apr 1, 2016 at 5:34 PM, Mikael Gerdin <mikael.gerdin at oracle.com> wrote:
> Hi Filipp
>
> On 2016-04-01 16:27, Filipp Zhinkin wrote:
>>
>> Hi Mikael,
>>
>> On Thu, Mar 31, 2016 at 7:25 PM, Mikael Gerdin <mikael.gerdin at oracle.com>
>> wrote:
>>>
>>> Hi,
>>>
>>> I like the cleanup, can't we also remove CHeapArray in arrays.hpp?
>>
>>
>> Sure! I've missed that it is not used at all.
>
>
> Great!
>
>>
>>>
>>> As for the CMS change, I would prefer this instead (untested!):
>>> http://cr.openjdk.java.net/~mgerdin/pss-array/webrev/
>>
>>
>> Thanks, your implementation looks much better.
>> If you don't mind I'll incorporate it into my change.
>
>
> Go ahead, that was my intention.
>
>>
>> Also, it seems like in ParNewGeneration::collect we have to create
>> ResourceMark before ParScanThreadStateSet, right?
>
>
> There is a ResourceMark in the caller so I don't think it's needed.
> The old version of the code used resource allocation as well and was fine so
> I don't think there is a need to introduce another ResourceMark.
>
>
> /Mikael
>
>
>>
>> Thanks,
>> Filipp.
>>
>>>
>>> /Mikael
>>>
>>>
>>> On 2016-03-31 17:14, Vladimir Kozlov wrote:
>>>>
>>>>
>>>> Hi Filipp,
>>>>
>>>> Yes, this looks better. CCing to hotspot-dev for Runtime and GC groups
>>>> to look on.
>>>>
>>>> Thanks,
>>>> Vladimir
>>>>
>>>> On 3/31/16 8:08 AM, Filipp Zhinkin wrote:
>>>>>
>>>>>
>>>>> Hi Vladimir,
>>>>>
>>>>> thank you for looking at this change.
>>>>>
>>>>> On Wed, Mar 30, 2016 at 1:18 AM, Vladimir Kozlov
>>>>> <vladimir.kozlov at oracle.com> wrote:
>>>>>>
>>>>>>
>>>>>> Nice clean up but I don't see any source code removed. What benefits
>>>>>> we have
>>>>>> then?
>>>>>> I understand that we don't generate subclasses for ResourceArray and
>>>>>> use
>>>>>> GrowableArray. But it will not save space I think.
>>>>>> What prevents us to remove ResourceArray at all?
>>>>>
>>>>>
>>>>>
>>>>> CMS's ParScanThreadStateSet is inherited from ResourceArray,
>>>>> so it should be updated before removing ResourceArray:
>>>>>
>>>>> http://cr.openjdk.java.net/~fzhinkin/8149374/webrev.01/
>>>>>
>>>>>>
>>>>>> On 3/11/16 3:42 AM, Filipp Zhinkin wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> please review a fix for JDK-8149374:
>>>>>>>
>>>>>>> Webrev: http://cr.openjdk.java.net/~fzhinkin/8149374/webrev.00/
>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8149374
>>>>>>> Testing done: hotspot_all tests + CTW
>>>>>>>
>>>>>>> I've replaced all usages of collections defined via define_array and
>>>>>>> define_stack macros with GrowableArray.
>>>>>>>
>>>>>>> There are good and bad news regarding performance impact of that
>>>>>>> change.
>>>>>>> Unfortunately, C1 compilation time for CTW-scenario w/ release bits
>>>>>>> increased from 51.07±0.28s to 52.99±0.23s (it's about 3.5%).
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> It is acceptable regression I think. I don't think we should optimize
>>>>>> and
>>>>>> make more complex GrowableArray just to save 0.5% of performance for
>>>>>> C2.
>>>>>
>>>>>
>>>>>
>>>>> As long as GrowableArray is used in different Hotspot's subsystems it
>>>>> may be beneficial to optimize it,
>>>>> but I've executed SPECjvm2008's startup.* benchmarks and there were no
>>>>> significant difference.
>>>>>
>>>>> If ~3% regression is OK for C1 then I'm fine with leaving
>>>>> GrowableArray's initialization
>>>>> in its current state unless there will be other reasons to speed it up.
>>>>>
>>>>> Thanks,
>>>>> Filipp.
>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> Vladimir
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Such difference caused by eager initialization of GrowableArray's
>>>>>>> backing array elements [1]. I can imagine when we actually need to
>>>>>>> force
>>>>>>> initialization and de-initialization during array's
>>>>>>> growing/destruction, but for some types like c++ primitive types or
>>>>>>> pointers such initialization does not make much sense, because
>>>>>>> GrowableArray is not allowing to access an element which was not
>>>>>>> explicitly placed inside of it. And as long as GrowableArray most
>>>>>>> widely used to store pointers we're simply wasting the time with
>>>>>>> initialization.
>>>>>>>
>>>>>>> I've measured CTW time with following workaround which implements
>>>>>>> initialization for numeric types and pointers as no-op and C1
>>>>>>> compilation time returned back to values that were measured before
>>>>>>> original change (51.06±0.24s):
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~fzhinkin/growableArrayInitialization/webrev/
>>>>>>>
>>>>>>>
>>>>>>> I've also measured C2 compilation time and it dropped down by a few
>>>>>>> seconds too: 1138±9s w/o GrowableArray's change and 1132±5s w/ it.
>>>>>>>
>>>>>>> Summing up: I guess we should avoid GrowableArray's backing array
>>>>>>> initialization for some types, don't we?
>>>>>>>
>>>>>>> Best regards,
>>>>>>> Filipp
>>>>>>>
>>>>>>> [1]
>>>>>>>
>>>>>>>
>>>>>>> http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/file/323b8370b0f6/src/share/vm/utilities/growableArray.hpp#l165
>>>>>>>
>>>>>>>
>>>>>>
>>>
>