Commit 21406928 authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

sched: Tweak sched_latency and min_granularity 



Allow LAST_BUDDY to kick in sooner, improving cache utilization as soon as
a second buddy pair arrives on scene.  The cost is latency starting to climb
sooner, the tbenefit for tbench 8 on my Q6600 box is ~2%.  No detrimental
effects noted in normal idesktop usage.

Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301285.6785.34.camel@marge.simson.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a64692a3

kernel/sched_fair.c

+6 −6
Original line number Diff line number Diff line
@@ -35,8 +35,8 @@ 
 * (to see the precise effective timeslice length of your workload,

 *  run vmstat and monitor the context-switches (cs) field)

 */

unsigned int sysctl_sched_latency = 5000000ULL;

unsigned int normalized_sysctl_sched_latency = 5000000ULL;

unsigned int sysctl_sched_latency = 6000000ULL;

unsigned int normalized_sysctl_sched_latency = 6000000ULL;



/*

 * The initial- and re-scaling of tunables is configurable
@@ -52,15 +52,15 @@ enum sched_tunable_scaling sysctl_sched_tunable_scaling 


/*

 * Minimal preemption granularity for CPU-bound tasks:

 * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)

 * (default: 2 msec * (1 + ilog(ncpus)), units: nanoseconds)

 */

unsigned int sysctl_sched_min_granularity = 1000000ULL;

unsigned int normalized_sysctl_sched_min_granularity = 1000000ULL;

unsigned int sysctl_sched_min_granularity = 2000000ULL;

unsigned int normalized_sysctl_sched_min_granularity = 2000000ULL;



/*

 * is kept at sysctl_sched_latency / sysctl_sched_min_granularity

 */

static unsigned int sched_nr_latency = 5;

static unsigned int sched_nr_latency = 3;



/*

 * After fork, child runs first. If set to 0 (default) then

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