[crac] RFR: 8373784: [CRaC] VM Option to require perfect CPU fit [v2]

[Radim Vansa]

On Wed, 7 Jan 2026 15:37:43 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

>> Right now CRaC will refuse to restore from the image if it is not compatible with current CPU as it assumes extra features. This check can be only relaxed with -XX:+UnlockExperimentalVMOptions -XX:+IgnoreCPUFeatures.
>> 
>> In scenarios with -XX:CRaCIgnoreRestoreIfUnavailable it might be favorable to skip the restore and proceed with running the application from scratch with all CPU features if the image has these restricted. Therefore I propose to create a new option -XX:CheckCPUFeatures with these values:
>> * compatible - this is the current behaviour (default)
>> * exact - require CPU features from the image to match perfectly
>> * skip - the same behaviour as `-XX:+IgnoreCPUFeatures`.
>> 
>> The current `-XX:+IgnoreCPUFeatures` option will be deprecated.
>
> Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Minor fixups

@TimPushkin @jankratochvil Could I get this approved please, or are there further requests for a change?

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PR Comment: https://git.openjdk.org/crac/pull/285#issuecomment-3722902987