sched: Add sysctl_sched_shares_window
Introduce a new sysctl for the shares window and disambiguate it from
sched_time_avg.
A 10ms window appears to be a good compromise between accuracy and performance.
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101115234938.112173964@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index b320753..6c84439 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -89,6 +89,13 @@
const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+/*
+ * The exponential sliding window over which load is averaged for shares
+ * distribution.
+ * (default: 10msec)
+ */
+unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
+
static const struct sched_class fair_sched_class;
/**************************************************************
@@ -688,7 +695,7 @@
#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
static void update_cfs_load(struct cfs_rq *cfs_rq)
{
- u64 period = sched_avg_period();
+ u64 period = sysctl_sched_shares_window;
u64 now, delta;
unsigned long load = cfs_rq->load.weight;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 3132b25..9b520d7 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -333,6 +333,13 @@
.proc_handler = proc_dointvec,
},
{
+ .procname = "sched_shares_window",
+ .data = &sysctl_sched_shares_window,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {
.procname = "timer_migration",
.data = &sysctl_timer_migration,
.maxlen = sizeof(unsigned int),