RFR: JDK-8202384: Introduce altserver jvm variant with speculative execution disabled

[Erik Joelsson]

On 2018-06-07 11:56, jesper.wilhelmsson at oracle.com wrote:
>> On 6 Jun 2018, at 06:17, David Holmes <david.holmes at oracle.com 
>> <mailto:david.holmes at oracle.com>> wrote:
>>
>> Hi Erik, Jesper,
>>
>>
>> So "benevolent dictatorship"?  ;-)
>>
>> My main concern is that the updated toolchains that support this have 
>> all been produced in a mad rush and quite frankly I expect them to be 
>> buggy. I don't think it is hard to enable the builder of OpenJDK to 
>> have full choice and control here.
>
> My assumption has been, and still is, that we're not the only ones 
> that will use gcc 7.3.0 with these flags. If there were bugs in the 
> new code they would most likely have been found already. The 
> experience from our own work in this area is that the bugs are 
> unlikely to be crashes due to the new code, but rather weird corner 
> cases where the new code is not inserted where it was needed, leaving 
> speculative execution unblocked in that single case.
>
> That said, I have no strong opinions on what is possible to configure 
> in the build, as long as the Oracle OpenJDK builds comes with two JVM 
> libraries and one copy of all other libraries. But that is of course a 
> slightly different issue as long as it is possible to do.
>
I just don't think the extra work is warranted or should be prioritized 
at this point. I also cannot think of a combination of options required 
for what you are suggesting that wouldn't be confusing to the user. If 
someone truly feels like these flags are forced on them and can't live 
with them, we or preferably that person can fix it then. I don't think 
that's dictatorship. OpenJDK is still open source and anyone can contribute.

/Erik