[14] RFR(XS): 8229158: make UseSwitchProfiling non-experimental or false by-default

[Christian Hagedorn]

Hi David

On 06.08.19 13:17, David Holmes wrote:
> Hi Christian,
> 
> On 6/08/2019 8:28 pm, Christian Hagedorn wrote:
>> Hi
>>
>> Please review the following enhancement:
>> https://bugs.openjdk.java.net/browse/JDK-8229158
>> http://cr.openjdk.java.net/~thartmann/8229158/webrev.00/
>>
>> This just changes the flag UseSwitchProfiling from experimental to 
>> diagnostic.
> 
> hotspot-compiler-dev seems like a better list for this change as that is 
> where the original code was reviewed. In particular I think you need to 
> get buy-in from the people that provided this code in the first place - 
> who would be Aleksey Shipilev and Roland Westrelin.
> 
> http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2018-March/028595.html 

Yes, you are right, would have been the better list!

> To be clear, the rationale for this change is that there is a general 
> expectation that an experimental flag of the form UseX is used to turn 
> on an experimental feature X (that would be off by default). Here we 
> appear to have functionality that should always be on but we want a flag 
> to allow it to be turned off "just in case". Such a flag (if not 
> product) would therefore be better as diagnostic.

This sounds reasonable, thanks for the detailed explanation!

Best regards,
Christian