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Commit 38ad464d authored by Ingo Molnar's avatar Ingo Molnar
Browse files

sched: uniform tunings 



use the same defaults on both UP and SMP.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent eba1ed4b

kernel/sched.c

+0 −28
Original line number Diff line number Diff line
@@ -4898,32 +4898,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) 
 */

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

/*

 * This is how migration works:
@@ -6491,12 +6465,10 @@ void __init sched_init_smp(void) 
	/* Move init over to a non-isolated CPU */

	if (set_cpus_allowed(current, non_isolated_cpus) < 0)

		BUG();

	sched_init_granularity();

}

#else

void __init sched_init_smp(void)

{

	sched_init_granularity();

}

#endif /* CONFIG_SMP */