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

[Jan Kratochvil]

On Wed, 7 Jan 2026 15:31:42 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

>> src/hotspot/share/runtime/crac.cpp line 824:
>> 
>>> 822:       return;
>>> 823:     }
>>> 824:     ignore = true;
>> 
>> This has only local effect, `VM_Version::ignore_cpu_features()` would still return `false`. But that is a part of the `-XX:CPUFeatures=ignore` vs. `-XX:+IgnoreCPUFeatures` unification so it may be OK here.
>
> Not sure what you're suggesting. If `-XX:CPUFeatures=ignore` is set on checkpoint the function will always return `true`, because the features are not stored anyway, so the `CheckCPUFeatures` is practically ignored. Are you saying that we should emit some warning in here?

I was just bringing up ZULU-75248 is unfixed so I cannot say what `-XX:CheckCPUFeatures=skip` really should do. OK to resolve this thread.

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PR Review Comment: https://git.openjdk.org/crac/pull/285#discussion_r2669936976