clk: qcom: clk-cpu-osm: Limit performance cluster to 2323200 kHz

On the performance cluster, all frequencies above 2323200 kHz use an obscene
amount of power compared to 2323200 kHz. Using an AES-based CPU benchmark in
the kernel, it was found that 2323200 kHz yields 89.4% the performance of the
2649600 kHz frequency, while using only 53.5% as much power.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Adam W. Willis <return.of.octobot@gmail.com>

drivers/clk/qcom/clk-cpu-osm.c

@@ -785,6 +785,17 @@ static int osm_cpufreq_cpu_init(struct cpufreq_policy *policy)
 		if (core_count != parent->max_core_count)
 			table[i].frequency = CPUFREQ_ENTRY_INVALID;
 
+		/*
+		 * Limit perfcl to 2323200 kHz to save power, since all
+		 * frequencies above that on perfcl use an exponentially higher
+		 * amount of power.
+		 */
+		if (cpumask_intersects(get_cpu_mask(policy->cpu),
+				       cpu_perf_mask)) {
+			if (table[i].frequency > 2323200)
+				break;
+		}
+
 		/*
 		 * Two of the same frequencies with the same core counts means
 		 * end of table.