I guess technically CAT and RDT are not ISA extensions because they are managed by MSRs. I was thinking of aspects of BMI, but I am sure that large-scale buyers

I guess technically CAT and RDT are not ISA extensions because they are managed by MSRs. I was thinking of aspects of BMI, but I am sure that large-scale buyers had input into things like vector extensions, PMU features, and the things you mentioned as well.