sched/topology: Don't enable EAS on SMT systems (38502ab4) · Commits · 戴 / test

EAS already requires asymmetric CPU capacities to be enabled, and mixing this with SMT is an aberration, but better be safe than sorry. Reviewed-by:

kernel/sched/topology.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -317,8 +317,9 @@ static void sched_energy_set(bool has_eas)
		* EAS can be used on a root domain if it meets all the following conditions:
		* 1. an Energy Model (EM) is available;
		* 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
		* 3. the EM complexity is low enough to keep scheduling overheads low;
		* 4. schedutil is driving the frequency of all CPUs of the rd;
		* 3. no SMT is detected.
		* 4. the EM complexity is low enough to keep scheduling overheads low;
		* 5. schedutil is driving the frequency of all CPUs of the rd;
		*
		* The complexity of the Energy Model is defined as:
		*
		@@ -360,6 +361,13 @@ static bool build_perf_domains(const struct cpumask *cpu_map)
		goto free;
		}

		/* EAS definitely does not handle SMT */
		if (sched_smt_active()) {
		pr_warn("rd %*pbl: Disabling EAS, SMT is not supported\n",
		cpumask_pr_args(cpu_map));
		goto free;
		}

		for_each_cpu(i, cpu_map) {
		/* Skip already covered CPUs. */
		if (find_pd(pd, i))