On 13-Mar 15:09, Peter Zijlstra wrote: > On Fri, Feb 08, 2019 at 10:05:40AM +0000, Patrick Bellasi wrote: > > +static inline unsigned int uclamp_none(int clamp_id) > > +{ > > + if (clamp_id == UCLAMP_MIN) > > + return 0; > > + return SCHED_CAPACITY_SCALE; > > +} > > + > > +static inline void uclamp_rq_update(struct rq *rq, unsigned int clamp_id) > > +{ > > + struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket; > > + unsigned int max_value = uclamp_none(clamp_id); > > That's 1024 for uclamp_max > > > + unsigned int bucket_id; > > + > > + /* > > + * Both min and max clamps are MAX aggregated, thus the topmost > > + * bucket with some tasks defines the rq's clamp value. > > + */ > > + bucket_id = UCLAMP_BUCKETS; > > + do { > > + --bucket_id; > > + if (!rq->uclamp[clamp_id].bucket[bucket_id].tasks) > > + continue; > > + max_value = bucket[bucket_id].value; > > but this will then _lower_ it. That's not a MAX aggregate. For uclamp_max we want max_value=1024 when there are no active tasks, which means: no max clamp enforced on CFS/RT "idle" cpus. If instead there are active RT/CFS tasks then we want the clamp value of the max group, which means: MAX aggregate active clamps. That's what the code above does and the comment says. > > + break; > > + } while (bucket_id); > > + > > + WRITE_ONCE(rq->uclamp[clamp_id].value, max_value); > > +} -- #include <best/regards.h> Patrick Bellasi