RFR (XXS): 8247748: Use default alpha for G1 adaptive IHOP allocation rate calculation
thomas.schatzl at oracle.com
Thu Jun 18 19:25:44 UTC 2020
On 18.06.20 21:18, Thomas Schatzl wrote:
> On 18.06.20 20:45, Luo, Ziyi wrote:
>> Hi Thomas,
>> I am a little bit confused here.
>> According to the TruncatedSeq constructor, the alpha is used to construct
>> When adding a new value to AbsSeq, the weight of the new val is (1.0 -
>> Right now, in Adaptive IHOP, the weight of the new value is (1-0.95) =
>> 0.05. After changing alpha to the default 0.7, the weight is increased
>> to 0.3,
>> which actually emphasizes the most recent allocation rate and will
>> make the prediction spikier.
> you are right. I mostly went with my memory which apparently has
> been the complete opposite of what it does/did, which led to the CR
> title/description :(
> In my tests I could not see an actual difference in behavior so I
> figured it would be better to not deviate from the other, existing
> predictors instead of some other number as we do not have any
> explanation for the default value (of 0.7) either. I.e. something like
> "one magic number is better than two".
> For this (very weak) reason I would still like to make this change, but
> I am open to just retract this change.
> Thanks for making me aware of this!
just let me retract this RFR for now. I will take more time to find a
better reasoning for any change in that area.
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