HotSpot 17 merge

[Andrew John Hughes]

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...
-- 
Andrew :-)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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