sched: packing tasks

Try to minimize the number of CPUs that are used to handle the current
activity.
You can set a packing threshold for each CPUs and clusters to define above
which level you should use more CPUs
You can also set a performance threshold to define above which level, you
should use a more performant CPU

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

1 files changed, 47 insertions, 3 deletions

diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index 08b7847bf912..8d9080a8a7fd 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -280,12 +280,56 @@ static inline int cpu_corepower_flags(void)
 	return SD_SHARE_PKG_RESOURCES  | SD_SHARE_POWERDOMAIN;
 }
 
+/*
+ * power threshold should be filled according to platform info that can come
+ * from DT as an example. For now use default table
+ */
+static int core_pack_threshold[8][2] = {
+     /* pack, perf */
+	{ 50, 100},
+	{ 50, 100},
+	{ 50, 100},
+	{ 50, 100},
+	{ 40, 100},
+	{ 20, 100},
+	{ 20, 100},
+	{ 10, 100},
+};
+
+static int cpu_core_th(int cpu, int index)
+{
+	if (cpu < 8)
+		return (core_pack_threshold[cpu][index] * 1024) / 100 ;
+
+	return 0;
+}
+
+static int cluster_pack_threshold[8][2] = {
+     /* pack, perf */
+	{ 0, 100},
+	{ 0, 100},
+	{ 0, 100},
+	{ 0, 100},
+	{ 40, 60},
+	{ 40, 60},
+	{ 40, 60},
+	{ 40, 60},
+};
+
+static int cpu_cluster_th(int cpu, int index)
+{
+	if (cpu < 8)
+		return (cluster_pack_threshold[cpu][index] * 1024) / 100;
+
+	return 0;
+}
+
 static struct sched_domain_topology_level arm_topology[] = {
 #ifdef CONFIG_SCHED_MC
-	{ cpu_corepower_mask, cpu_corepower_flags, SD_INIT_NAME(GMC) },
-	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
+	{ cpu_corepower_mask, cpu_corepower_flags, cpu_core_th, SD_INIT_NAME(GMC) },
+	{ cpu_coregroup_mask, cpu_core_flags, cpu_core_th, SD_INIT_NAME(MC) },
 #endif
-	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
+	{ cpu_cpu_mask, NULL, cpu_cluster_th, SD_INIT_NAME(DIE) },
 	{ NULL, },
 };