PELT scales its util_sum and util_avg values via arch_scale_cpu_capacity(). If that function is passed the CPU's sched domain then it will reduce the scaling capacity if SD_SHARE_CPUCAPACITY is set. PELT does not pass in the sd however. The other caller of arch_scale_cpu_capacity, update_cpu_capacity(), does. This means util_sum and util_avg scale beyond the CPU capacity on SMT.
On an Intel i7-3630QM for example rq->cpu_capacity_orig is 589 but util_avg scales up to 1024. Fix this by passing in the sd in __update_load_avg() as well. Signed-off-by: Steve Muckle <smuc...@linaro.org> --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 61d485421bed..95d34b337152 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2731,7 +2731,7 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa, sa->last_update_time = now; scale_freq = arch_scale_freq_capacity(NULL, cpu); - scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + scale_cpu = arch_scale_cpu_capacity(cpu_rq(cpu)->sd, cpu); /* delta_w is the amount already accumulated against our next period */ delta_w = sa->period_contrib; -- 2.7.3