[RFC PATCH 04/13] sched:Decide group_imb using PJT's metric
Preeti U Murthy
preeti at linux.vnet.ibm.com
Thu Oct 25 06:25:27 EDT 2012
Additional parameters for deciding a sched group's imbalance status
which are calculated using the per entity load tracking are used.
Signed-off-by: Preeti U Murthy <preeti at linux.vnet.ibm.com>
---
kernel/sched/fair.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 67a916d..77363c6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3748,6 +3748,7 @@ struct lb_env {
int new_dst_cpu;
enum cpu_idle_type idle;
long imbalance;
+ long long load_imbalance; /* PJT metric equivalent of imbalance */
/* The set of CPUs under consideration for load-balancing */
struct cpumask *cpus;
@@ -4513,6 +4514,11 @@ static inline void update_sg_lb_stats(struct lb_env *env,
unsigned long load, max_cpu_load, min_cpu_load;
unsigned int balance_cpu = -1, first_idle_cpu = 0;
unsigned long avg_load_per_task = 0;
+
+ /* Decide imb based on PJT's metric */
+ u64 cpu_runnable_load, max_cpu_runnable_load, min_cpu_runnable_load;
+ u64 avg_sg_load_per_task = 0;
+
int i;
if (local_group)
@@ -4521,6 +4527,8 @@ static inline void update_sg_lb_stats(struct lb_env *env,
/* Tally up the load of all CPUs in the group */
max_cpu_load = 0;
min_cpu_load = ~0UL;
+ max_cpu_runnable_load = 0;
+ min_cpu_runnable_load = ~0ULL;
max_nr_running = 0;
min_nr_running = ~0UL;
@@ -4545,6 +4553,12 @@ static inline void update_sg_lb_stats(struct lb_env *env,
if (min_cpu_load > load)
min_cpu_load = load;
+ cpu_runnable_load = cpu_rq(i)->cfs.runnable_load_avg;
+ if (cpu_runnable_load > max_cpu_runnable_load)
+ max_cpu_runnable_load = cpu_runnable_load;
+ if (min_cpu_runnable_load > cpu_runnable_load)
+ min_cpu_runnable_load = cpu_runnable_load;
+
if (nr_running > max_nr_running)
max_nr_running = nr_running;
if (min_nr_running > nr_running)
@@ -4604,10 +4618,13 @@ static inline void update_sg_lb_stats(struct lb_env *env,
* normalized nr_running number somewhere that negates
* the hierarchy?
*/
- if (sgs->sum_nr_running)
+ if (sgs->sum_nr_running) {
avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
+ avg_sg_load_per_task = sgs->group_cfs_runnable_load / sgs->sum_nr_running;
+ }
- if ((max_cpu_load - min_cpu_load) >= avg_load_per_task &&
+ /* The following decision is made on PJT's metric */
+ if ((max_cpu_runnable_load - min_cpu_runnable_load) >= avg_sg_load_per_task &&
(max_nr_running - min_nr_running) > 1)
sgs->group_imb = 1;
@@ -5047,6 +5064,7 @@ out_balanced:
ret:
env->imbalance = 0;
+ env->load_imbalance = 0;
return NULL;
}
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