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[tip:sched/core] sched: Tweak sched_latency and min_granularity

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From: tip-bot for Mike Galbraith
Subject: [tip:sched/core] sched: Tweak sched_latency and min_granularity
Date: Thursday, March 11, 2010 - 11:31 am

Commit-ID:  21406928afe43f1db6acab4931bb8c886f4d04ce
Gitweb:     http://git.kernel.org/tip/21406928afe43f1db6acab4931bb8c886f4d04ce
Author:     Mike Galbraith <efault@gmx.de>
AuthorDate: Thu, 11 Mar 2010 17:17:15 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 11 Mar 2010 18:32:51 +0100

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: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301285.6785.34.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched_fair.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 69e5820..d19df5b 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -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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Messages in current thread:
[patch 0/12] sched: fastpath cycle recovery, Mike Galbraith, (Thu Mar 11, 2:49 am)
Re: [patch 1/12] sched: ratelimit nohz, Mike Galbraith, (Thu Mar 11, 2:50 am)
Re: [patch 2/12] sched: remove avg_wakeup, Mike Galbraith, (Thu Mar 11, 2:51 am)
Re: [patch 3/12] sched: remove avg_overlap, Mike Galbraith, (Thu Mar 11, 2:52 am)
Re: [patch 4/12] sched: cleanup/optimize clock updates, Mike Galbraith, (Thu Mar 11, 2:53 am)
Re: [patch 5/12] sched: tweak sched_latency and min_granul ..., Mike Galbraith, (Thu Mar 11, 2:54 am)
Re: [patch 6/12] sched: fix select_idle_sibling(), Mike Galbraith, (Thu Mar 11, 2:56 am)
Re: [patch 7/12] sched: remove NORMALIZED_SLEEPER, Mike Galbraith, (Thu Mar 11, 2:57 am)
Re: [patch 8/12] sched: remove FAIR_SLEEPERS feature, Mike Galbraith, (Thu Mar 11, 2:58 am)
Re: [patch 9/12] sched: remove WAKEUP_SYNC feature, Mike Galbraith, (Thu Mar 11, 2:59 am)
Re: [patch 11/12] sched: remove ASYM_GRAN feature, Mike Galbraith, (Thu Mar 11, 3:01 am)
Re: [patch 10/12] sched: remove SYNC_WAKEUPS feature, Mike Galbraith, (Thu Mar 11, 3:03 am)
Re: [patch 12/12] sched: remove AFFINE_WAKEUPS feature, Mike Galbraith, (Thu Mar 11, 3:04 am)
[tip:sched/core] sched: Rate-limit nohz, tip-bot for Mike Gal ..., (Thu Mar 11, 11:30 am)
[tip:sched/core] sched: Remove avg_wakeup, tip-bot for Mike Gal ..., (Thu Mar 11, 11:30 am)
[tip:sched/core] sched: Remove avg_overlap, tip-bot for Mike Gal ..., (Thu Mar 11, 11:31 am)
[tip:sched/core] sched: Cleanup/optimize clock updates, tip-bot for Mike Gal ..., (Thu Mar 11, 11:31 am)
[tip:sched/core] sched: Tweak sched_latency and min_granul ..., tip-bot for Mike Gal ..., (Thu Mar 11, 11:31 am)
[tip:sched/core] sched: Fix select_idle_sibling(), tip-bot for Mike Gal ..., (Thu Mar 11, 11:32 am)
[tip:sched/core] sched: Remove NORMALIZED_SLEEPER, tip-bot for Mike Gal ..., (Thu Mar 11, 11:32 am)
[tip:sched/core] sched: Remove FAIR_SLEEPERS feature, tip-bot for Mike Gal ..., (Thu Mar 11, 11:32 am)
[tip:sched/core] sched: Remove WAKEUP_SYNC feature, tip-bot for Mike Gal ..., (Thu Mar 11, 11:32 am)
[tip:sched/core] sched: Remove SYNC_WAKEUPS feature, tip-bot for Mike Gal ..., (Thu Mar 11, 11:33 am)
[tip:sched/core] sched: Remove ASYM_GRAN feature, tip-bot for Mike Gal ..., (Thu Mar 11, 11:33 am)
[tip:sched/core] sched: Remove AFFINE_WAKEUPS feature, tip-bot for Mike Gal ..., (Thu Mar 11, 11:33 am)
Re: [tip:sched/core] sched: Remove AFFINE_WAKEUPS feature, Yong Zhang, (Thu Mar 11, 8:23 pm)
Re: [tip:sched/core] sched: Remove AFFINE_WAKEUPS feature, Mike Galbraith, (Thu Mar 11, 9:37 pm)