HotSpot 17 merge

[Joe Darcy]

Andrew John Hughes wrote:
> On 17 May 2010 18:08, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>   
>> Andrew,
>>
>> yes, you should revert/remove the 6909480 changeset in OpenJDK6 after merge
>> with hs17
>>
>> Vladimir
>>
>> Andrew John Hughes wrote:
>>     
>>> On 17 May 2010 17:29, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>>>       
>>>> When we released jdk6u18 (hs16) there were 2 EA critical bugs
>>>> for which we did not have time to fix in 6u18:
>>>>
>>>> http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/f96a1a986f7b
>>>> http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/7fee0a6cc6d4
>>>>
>>>> In short, with escape analysis the generated code produces NULL(0)
>>>> instead of expected (stored) values.
>>>>
>>>> There was no enough time for full testing in 6u18 and changes were too
>>>> big.
>>>> I would advice to not use EA with HS16.
>>>>
>>>> In hs17 we enabled EA again and tested it until 6u21 release in which
>>>> the default flag's value is set to false but you can specify the flag
>>>> on command line to enable EA. There are few problems which needs to be
>>>> fixed before we enable EA by default.
>>>>
>>>> Andrew, you are right to not merge changes from hs16. And you can use
>>>> the flag on command line for HS17 instead of patch to enable EA.
>>>> It would be easier for benchmarking.
>>>>
>>>>         
>>> Unfortunately it's not a matter of choosing not to merge the change,
>>> but having to revert it as it's already part of OpenJDK6 from the
>>> earlier hs16 merge (currently showing up as a difference between
>>> OpenJDK6's HotSpot and the hs17 branch).  See the results and
>>> discussion in the mail I just posted.
>>>
>>>       
>>>> Vladimir
>>>>
>>>> Andrew John Hughes wrote:
>>>>         
>>>>> On 16 May 2010 18:22, Andrew Haley <aph at redhat.com> wrote:
>>>>>           
>>>>>> On 05/16/2010 05:14 PM, Andrew John Hughes wrote:
>>>>>>             
>>>>>>> The webrev is here:
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~andrew/jdk6-hs17-merge/
>>>>>>>
>>>>>>> I'd also like to revert:
>>>>>>>
>>>>>>> 6909480: Disable Escape Analysis in jdk 6u18
>>>>>>> http://hg.openjdk.java.net/hsx/hsx16/master/rev/4ebd3f8407eb
>>>>>>>
>>>>>>> which isn't present in hs17 (and so remains a difference between jdk6
>>>>>>> and hs17) as, unlike jdk6's version, hs17 is based on the main HotSpot
>>>>>>> tree rather than the hs16 master.  I didn't include this in the merge
>>>>>>> because it's clearer what's going on if it appears as a separate
>>>>>>> change.
>>>>>>>               
>>>>>> Ahh, good catch.
>>>>>>
>>>>>> Do we have any idea why escape analysis is disabled?
>>>>>>
>>>>>> Andrew.
>>>>>>
>>>>>>             
>>>>> I assume it wasn't stable enough in hs16, but the bug isn't visible.
>>>>> Can someone from the HotSpot team shed more light on this?
>>>>>           
>>>
>>>       
>
> Yeah :-)
>
> Just waiting for the go-ahead from Joe now...
>   

Hello.

I just finished looking over the lengthy patch.

I approve the patch to update OpenJDK 6 to HS17 going back along with 
the subsequence reverting of 6909480.

Thanks,

-Joe