When both cfs and rt tasks compete to run on a CPU, we can see some frequency drops with schedutil governor. In such case, the cfs_rq's utilization doesn't reflect anymore the utilization of cfs tasks but only the remaining part that is not used by rt tasks. We should monitor the stolen utilization and take it into account when selecting OPP.
Patch 1 tracks utilization of rt_rq. Patch 2 adds the rt_rq's utilization when selection OPP for cfs tasks This patchset doesn't change the OPP selection policy for RT tasks Vincent Guittot (2): sched/rt: add utilization tracking cpufreq/schedutil: add rt utilization tracking kernel/sched/cpufreq_schedutil.c | 2 +- kernel/sched/fair.c | 21 +++++++++++++++++++++ kernel/sched/rt.c | 9 +++++++++ kernel/sched/sched.h | 3 +++ 4 files changed, 34 insertions(+), 1 deletion(-) -- 2.7.4