MSR_ARCH_INFO_MPERF_INDEX
[MSR_ARCH_INFO_MPERF_INDEX] = {
return cpuid_has_aperf_mperf && msr_counter_arch_infos[MSR_ARCH_INFO_APERF_INDEX].present && msr_counter_arch_infos[MSR_ARCH_INFO_MPERF_INDEX].present;
msr_counter_arch_infos[MSR_ARCH_INFO_MPERF_INDEX].needed = need_amperf;