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Commit 5f6d858e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: speed up and simplify vslice calculations 



speed up and simplify vslice calculations.

[ From: Mike Galbraith <efault@gmx.de>: build fix ]

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b0ffd246

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

kernel/sched_debug.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/sched_fair.c

+9 −6
Original line number Diff line number Diff line
@@ -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;

}



/*

kernel/sysctl.c

+3 −6
Original line number Diff line number Diff line
@@ -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,