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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2007-10-15 17:00:12 +0200
committerIngo Molnar <mingo@elte.hu>2007-10-15 17:00:12 +0200
commit5f6d858ecca78f71755859a346d845e302973cd1 (patch)
tree5422f6ff9aa7ffab4c708432de84a79e52e503d9
parentb0ffd246ea947a037746e725bd461bb7e809a4b3 (diff)
sched: speed up and simplify vslice calculations
speed up and simplify vslice calculations. [ From: Mike Galbraith <efault@gmx.de>: build fix ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--include/linux/sched.h2
-rw-r--r--kernel/sched_debug.c2
-rw-r--r--kernel/sched_fair.c15
-rw-r--r--kernel/sysctl.c9
4 files changed, 14 insertions, 14 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d5daca4bcc6b..97f736b749c2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1400,7 +1400,7 @@ extern void sched_idle_next(void);
#ifdef CONFIG_SCHED_DEBUG
extern unsigned int sysctl_sched_latency;
-extern unsigned int sysctl_sched_min_granularity;
+extern unsigned int sysctl_sched_nr_latency;
extern unsigned int sysctl_sched_wakeup_granularity;
extern unsigned int sysctl_sched_batch_wakeup_granularity;
extern unsigned int sysctl_sched_child_runs_first;
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index be79cd6d9e80..995bbd384a97 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -210,7 +210,7 @@ static int sched_debug_show(struct seq_file *m, void *v)
#define PN(x) \
SEQ_printf(m, " .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
PN(sysctl_sched_latency);
- PN(sysctl_sched_min_granularity);
+ PN(sysctl_sched_nr_latency);
PN(sysctl_sched_wakeup_granularity);
PN(sysctl_sched_batch_wakeup_granularity);
PN(sysctl_sched_child_runs_first);
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index ec0569e59e24..ae2d4b08e782 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -46,7 +46,7 @@ const_debug unsigned int sysctl_sched_child_runs_first = 1;
* Minimal preemption granularity for CPU-bound tasks:
* (default: 2 msec, units: nanoseconds)
*/
-unsigned int sysctl_sched_min_granularity __read_mostly = 2000000ULL;
+const_debug unsigned int sysctl_sched_nr_latency = 20;
/*
* sys_sched_yield() compat mode
@@ -222,8 +222,7 @@ static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
static u64 __sched_period(unsigned long nr_running)
{
u64 period = sysctl_sched_latency;
- unsigned long nr_latency =
- sysctl_sched_latency / sysctl_sched_min_granularity;
+ unsigned long nr_latency = sysctl_sched_nr_latency;
if (unlikely(nr_running > nr_latency)) {
period *= nr_running;
@@ -245,11 +244,15 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
static u64 __sched_vslice(unsigned long nr_running)
{
- u64 period = __sched_period(nr_running);
+ unsigned long period = sysctl_sched_latency;
+ unsigned long nr_latency = sysctl_sched_nr_latency;
- do_div(period, nr_running);
+ if (unlikely(nr_running > nr_latency))
+ nr_running = nr_latency;
- return period;
+ period /= nr_running;
+
+ return (u64)period;
}
/*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 97b15c27407f..230ca4eb57fe 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -222,14 +222,11 @@ static ctl_table kern_table[] = {
#ifdef CONFIG_SCHED_DEBUG
{
.ctl_name = CTL_UNNUMBERED,
- .procname = "sched_min_granularity_ns",
- .data = &sysctl_sched_min_granularity,
+ .procname = "sched_nr_latency",
+ .data = &sysctl_sched_nr_latency,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = &proc_dointvec_minmax,
- .strategy = &sysctl_intvec,
- .extra1 = &min_sched_granularity_ns,
- .extra2 = &max_sched_granularity_ns,
+ .proc_handler = &proc_dointvec,
},
{
.ctl_name = CTL_UNNUMBERED,

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