On Wednesday, March 16, 2016 09:07:52 PM Peter Zijlstra wrote: > On Wed, Mar 16, 2016 at 07:44:33PM +0000, Dietmar Eggemann wrote: > > intel_pstate (setpolicy()) is an exception but my humble guess is that > > systems with intel_pstate driver have X86_FEATURE_APERFMPERF support. > > A quick browse of the Intel SDM says you're right. It looks like > everything after Pentium-M; so Core-Solo/Core-Duo and onwards have > APERF/MPERF. > > And it looks like P6 class systems didn't have DVFS support at all, > which basically leaves P4 and Pentium-M as the only chips to have DVFS > support lacking APERF/MPERF. > > And while I haven't got any P4 based space heaters left, I might still > have a Pentium-M class laptop somewhere (if it still boots).
intel_pstate depends on APERF/MPERF, so it won't work with anything without them.
