not sure that powertop performs any specific MSRs at all, since most
of MSRs are
called correspondingly to c-state flags (has_cXXX), e.g.
__init:
if (model == 0x45 || model ==0x3D)
has_c8c9c10_res = 1;
and later:
if (has_c8c9c10_res) {
c8_before = get_msr(number, MSR_PKG_C8_RESIDENCY);
c9_before = get_msr(number, MSR_PKG_C9_RESIDENCY);
c10_before = get_msr(number, MSR_PKG_C10_RESIDENCY);
}
and so on.
but if the set is empty, you don't get any data, and the "emulation" side of
powertop
is likely a better choice... since there are C states, just not counters.