RFR(S): 8237375: SimpleThresholdPolicy misses CounterDecay timestamp initialization

[David Holmes]

On 22/01/2020 8:47 pm, Doerr, Martin wrote:
> Hi David,
> 
> I'll change it to update_last_timestamp before pushing.
> Can I add you as reviewer?

Sure.

Thanks,
David

> Best regards,
> Martin
> 
> 
>> -----Original Message-----
>> From: David Holmes <david.holmes at oracle.com>
>> Sent: Montag, 20. Januar 2020 22:54
>> To: Doerr, Martin <martin.doerr at sap.com>; 'hotspot-compiler-
>> dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
>> Cc: David Holmes <David.Holmes at oracle.com>
>> Subject: Re: RFR(S): 8237375: SimpleThresholdPolicy misses CounterDecay
>> timestamp initialization
>>
>> Hi Martin,
>>
>> On 21/01/2020 12:25 am, Doerr, Martin wrote:
>>> Hi,
>>>
>>> I'd like to fix warmup issues we observed in test
>>> compiler/c2/Test8004741.java.
>>>
>>> The issue is a missing timestamp initialization which leads to a
>>> premature counter decay at the first safepoint with -XX:-
>> TieredCompilation.
>>>
>>> Bug:
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8237375
>>>
>>> Webrev:
>>>
>>> http://cr.openjdk.java.net/~mdoerr/8237375_CounterDecay/webrev.00/
>>>
>>> The webrev applies on top of the preliminary fix for
>>> https://bugs.openjdk.java.net/browse/JDK-8235741.
>>>
>>> I'll wait until that one gets pushed.
>>>
>>> What it changes:
>>>
>>>    * Move class CounterDecay up
>>>    * Introduce reset_last_timestamp()
>>
>> "reset" suggests clearing or moving back to an original value to me. How
>> about just "set" or "update"?
>>
>> Cheers,
>> David
>>
>>>    * Use this function in decay() and in SimpleCompPolicy::initialize()
>>>
>>> Best regards,
>>>
>>> Martin
>>>