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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2007-10-15 17:00:12 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-10-15 17:00:12 +0200 |
| commit | 5f6d858ecca78f71755859a346d845e302973cd1 (patch) | |
| tree | 5422f6ff9aa7ffab4c708432de84a79e52e503d9 /kernel/sched_fair.c | |
| parent | b0ffd246ea947a037746e725bd461bb7e809a4b3 (diff) | |
| download | lwn-5f6d858ecca78f71755859a346d845e302973cd1.tar.gz lwn-5f6d858ecca78f71755859a346d845e302973cd1.zip | |
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>
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 15 |
1 files changed, 9 insertions, 6 deletions
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; } /* |