HotSpot 17 merge

[Vladimir Kozlov]

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?
> 
> 
>