Thread (50 messages) 50 messages, 3 authors, 2019-05-09

Re: [PATCH v8 11/16] sched/fair: uclamp: Add uclamp support to energy_compute()

From: Peter Zijlstra <peterz@infradead.org>
Date: 2019-05-09 12:51:16
Also in: linux-pm, lkml

On Tue, Apr 02, 2019 at 11:41:47AM +0100, Patrick Bellasi wrote:
quoted hunk ↗ jump to hunk
@@ -6484,11 +6494,29 @@ compute_energy(struct task_struct *p, int dst_cpu, struct perf_domain *pd)
 		 * it will not appear in its pd list and will not be accounted
 		 * by compute_energy().
 		 */
-		for_each_cpu_and(cpu, perf_domain_span(pd), cpu_online_mask) {
-			util = cpu_util_next(cpu, p, dst_cpu);
-			util = schedutil_energy_util(cpu, util);
-			max_util = max(util, max_util);
-			sum_util += util;
+		for_each_cpu_and(cpu, pd_mask, cpu_online_mask) {
+			util_cfs = cpu_util_next(cpu, p, dst_cpu);
+
+			/*
+			 * Busy time computation: utilization clamping is not
+			 * required since the ratio (sum_util / cpu_capacity)
+			 * is already enough to scale the EM reported power
+			 * consumption at the (eventually clamped) cpu_capacity.
+			 */
+			sum_util += schedutil_cpu_util(cpu, util_cfs, cpu_cap,
+						       ENERGY_UTIL, NULL);
+
+			/*
+			 * Performance domain frequency: utilization clamping
+			 * must be considered since it affects the selection
+			 * of the performance domain frequency.
+			 * NOTE: in case RT tasks are running, by default the
+			 * FREQUENCY_UTIL's utilization can be max OPP.
+			 */
+			tsk = cpu == dst_cpu ? p : NULL;
+			cpu_util = schedutil_cpu_util(cpu, util_cfs, cpu_cap,
+						      FREQUENCY_UTIL, tsk);
+			max_util = max(max_util, cpu_util);
 		}
That's a bit unfortunate; having to do both variants here, but I see
why. Nothing to be done about it I suppose.
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