On Tue, May 15, 2018 at 09:49:03PM -0700, Srinivas Pandruvada wrote: > intel_pstate has two operating modes: active and passive. In "active" > mode, the in-built scaling governor is used and in "passive" mode, > the driver can be used with any governor like "schedutil". In "active" > mode the utilization values from schedutil is not used and there is > a requirement from high performance computing use cases, not to read > any APERF/MPERF MSRs. In this case no need to use CPU cycles for > frequency invariant accounting by reading APERF/MPERF MSRs. > With this change frequency invariant account is only enabled in > "passive" mode.
WTH is active/passive? Is passive when we select performance governor? Also; you have to explain why using APERF/MPERF is bad in that case. Why do they care if we read those MSRs during the tick?
