Hi, On 06/08/18 17:39, Patrick Bellasi wrote:
[...] > @@ -223,13 +224,25 @@ static unsigned long sugov_get_util(struct sugov_cpu > *sg_cpu) > * utilization (PELT windows are synchronized) we can directly add them > * to obtain the CPU's actual utilization. > * > - * CFS utilization can be boosted or capped, depending on utilization > - * clamp constraints configured for currently RUNNABLE tasks. > + * CFS and RT utilizations can be boosted or capped, depending on > + * utilization constraints enforce by currently RUNNABLE tasks. > + * They are individually clamped to ensure fairness across classes, > + * meaning that CFS always gets (if possible) the (minimum) required > + * bandwidth on top of that required by higher priority classes. Is this a stale comment written before UCLAMP_SCHED_CLASS was introduced? It seems to apply to the below if branch only. > */ > - util = cpu_util_cfs(rq); > - if (util) > - util = uclamp_util(cpu_of(rq), util); > - util += cpu_util_rt(rq); > + util_cfs = cpu_util_cfs(rq); > + util_rt = cpu_util_rt(rq); > + if (sched_feat(UCLAMP_SCHED_CLASS)) { > + util = 0; > + if (util_cfs) > + util += uclamp_util(cpu_of(rq), util_cfs); > + if (util_rt) > + util += uclamp_util(cpu_of(rq), util_rt); > + } else { > + util = cpu_util_cfs(rq); > + util += cpu_util_rt(rq); > + util = uclamp_util(cpu_of(rq), util); > + } Best, - Juri