Vladimir Kozlov | 17 May 18:29 2010
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Re: HotSpot 17 merge

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.

Vladimir

Andrew John Hughes wrote:
> On 16 May 2010 18:22, Andrew Haley <aph@...> 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?


Gmane