RFR: 8240370: Provide Intel JCC Erratum opt-out

[Claes Redestad]

Hi Erik,

thanks for adding this!

I think you can move the flag definition from globals.hpp to 
globals_x86.hpp and leave the other platforms alone for this. There
are a number of x86-specific flags there already.

/Claes

On 2020-03-03 13:23, Erik Österlund wrote:
> Hi,
> 
> Today, the Intel JCC Erratum mitigation is automatically enabled when 
> running on an affected machine.
> While it is strongly recommended that customers run code in environments 
> with the micro code updates
> provided by Intel to mitigate the erratum, and hence are probably almost 
> always better off with the
> mitigation, there could be value in being able to opt out to analyze the 
> performance characteristics
> of an application, as a diagnostic option.
> 
> This patch adds a diagnostic option that allows you to opt out with: 
> -XX:-IntelJccErratum
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8240370/webrev.00/
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8240370
> 
> Thanks,
> /Erik