On Tue, Nov 17, 2020 at 1:00 PM Mathieu Chouquet-Stringer <me@mathieu.digital> wrote:
> I'm late to the party but it seems allowing MSR_IA32_ENERGY_PERF_BIAS > has the downside of flagging the kernel as tainted without telling you > why if you use something like x86_energy_perf_policy (from > tools/power/x86/x86_energy_perf_policy) which itself is used by tuned. I initially pushed back against a kernel interface for MSR_IA32_ENERGY_PERF_BIAS (cc: Len Brown, who tried mightily to convince me I was wrong here) on the grounds that it was exporting an implementation detail rather than providing a generic interface, and that it was something that could be done via userland instead. I thought we'd end up with more examples of similar functionality and could tie it into something more reasonable - history has proven me wrong on that. I think it's probably reasonable to dust off the driver that Len submitted however many years ago and push that into the kernel now.