Add a tunable to test a variety of different ways of setting load in smt.

-ck

---
 kernel/sched/bfs.c |   38 +++++++++++++++++++++++++++++++++++---
 kernel/sysctl.c    |    8 ++++++++
 2 files changed, 43 insertions(+), 3 deletions(-)

Index: linux-4.7.4-ck4/kernel/sched/bfs.c
===================================================================
--- linux-4.7.4-ck4.orig/kernel/sched/bfs.c	2016-09-16 15:41:51.408265873 +1000
+++ linux-4.7.4-ck4/kernel/sched/bfs.c	2016-09-16 16:00:58.817245964 +1000
@@ -151,6 +151,7 @@ int rr_interval __read_mostly = 6;
  * binary yes or no */
 
 int sched_interactive __read_mostly = 1;
+int sched_smt_load;
 
 /*
  * sched_iso_cpu - sysctl which determines the cpu percentage SCHED_ISO tasks
@@ -751,6 +752,7 @@ static unsigned long cpu_load_avg(struct
  * of a CPU with SMT siblings is in use.
  */
 #define SCHED_SMT_LOAD (890)
+#define SCHED_REMST_LOAD (SCHED_CAPACITY_SCALE - SCHED_SMT_LOAD)
 
 /*
  * Load of a CPU with smt siblings should be considered to be the load from all
@@ -759,11 +761,41 @@ static unsigned long cpu_load_avg(struct
  */
 static unsigned long smt_load_avg(struct rq *rq)
 {
-	unsigned long load = rq->soft_affined * SCHED_SMT_LOAD;
+	unsigned long load;
 	int cpu;
 
-	for_each_cpu(cpu, thread_cpumask(rq->cpu))
-		load += cpu_rq(cpu)->soft_affined * SCHED_SMT_LOAD;
+	switch (sched_smt_load) {
+		default:
+		case 0:
+			load = cpu_load_avg(rq);
+			goto out;
+		case 1:
+			load = rq->soft_affined * SCHED_SMT_LOAD;
+			for_each_cpu(cpu, thread_cpumask(rq->cpu))
+				load += cpu_rq(cpu)->soft_affined * SCHED_REMST_LOAD;
+			goto out;
+		case 2:
+			load = rq->soft_affined * SCHED_SMT_LOAD;
+			for_each_cpu(cpu, thread_cpumask(rq->cpu))
+				load += cpu_rq(cpu)->soft_affined * SCHED_SMT_LOAD;
+			goto out;
+		case 3:
+			load = cpu_load_avg(rq);
+			for_each_cpu(cpu, thread_cpumask(rq->cpu))
+				load += cpu_rq(cpu)->soft_affined * SCHED_REMST_LOAD;
+			goto out;
+		case 4:
+			load = cpu_load_avg(rq);
+			for_each_cpu(cpu, thread_cpumask(rq->cpu))
+				load += cpu_rq(cpu)->soft_affined * SCHED_SMT_LOAD;
+			goto out;
+		case 5:
+			load = cpu_load_avg(rq);
+			for_each_cpu(cpu, thread_cpumask(rq->cpu))
+				load += cpu_rq(cpu)->soft_affined * SCHED_CAPACITY_SCALE;
+			goto out;
+	}
+out:
 	return load;
 }
 
Index: linux-4.7.4-ck4/kernel/sysctl.c
===================================================================
--- linux-4.7.4-ck4.orig/kernel/sysctl.c	2016-09-16 15:41:32.374369688 +1000
+++ linux-4.7.4-ck4/kernel/sysctl.c	2016-09-16 15:46:13.608943622 +1000
@@ -131,6 +131,7 @@ static int __read_mostly one_thousand =
 extern int rr_interval;
 extern int sched_interactive;
 extern int sched_iso_cpu;
+extern int sched_smt_load;
 #endif
 #ifdef CONFIG_PRINTK
 static int ten_thousand = 10000;
@@ -1041,6 +1042,13 @@ static struct ctl_table kern_table[] = {
 		.extra1		= &zero,
 		.extra2		= &one_hundred,
 	},
+	{
+		.procname	= "smt_load",
+		.data		= &sched_smt_load,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
 #endif
 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
 	{