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sched: uniform tunings 

use the same defaults on both UP and SMP.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Ingo Molnar 2007-10-15 17:00:02 +02:00
parent eba1ed4b7e
commit 38ad464d41
1 changed files with 0 additions and 28 deletions
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28
kernel/sched.c
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@ -4898,32 +4898,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
*/ */
cpumask_t nohz_cpu_mask = CPU_MASK_NONE; cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
/*
* Increase the granularity value when there are more CPUs,
* because with more CPUs the 'effective latency' as visible
* to users decreases. But the relationship is not linear,
* so pick a second-best guess by going with the log2 of the
* number of CPUs.
*
* This idea comes from the SD scheduler of Con Kolivas:
*/
static inline void sched_init_granularity(void)
{
unsigned int factor = 1 + ilog2(num_online_cpus());
const unsigned long limit = 100000000;
sysctl_sched_min_granularity *= factor;
if (sysctl_sched_min_granularity > limit)
sysctl_sched_min_granularity = limit;
sysctl_sched_latency *= factor;
if (sysctl_sched_latency > limit)
sysctl_sched_latency = limit;
sysctl_sched_runtime_limit = sysctl_sched_latency;
sysctl_sched_wakeup_granularity = sysctl_sched_min_granularity / 2;
}
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
/* /*
* This is how migration works: * This is how migration works:
@ -6491,12 +6465,10 @@ void __init sched_init_smp(void)
/* Move init over to a non-isolated CPU */ /* Move init over to a non-isolated CPU */
if (set_cpus_allowed(current, non_isolated_cpus) < 0) if (set_cpus_allowed(current, non_isolated_cpus) < 0)
BUG(); BUG();
sched_init_granularity();
} }
#else #else
void __init sched_init_smp(void) void __init sched_init_smp(void)
{ {
sched_init_granularity();
} }
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */