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authorZou Nan hai <nanhai.zou@intel.com>2007-11-26 21:21:49 +0100
committerIngo Molnar <mingo@elte.hu>2007-11-26 21:21:49 +0100
commit722aab0c3bbd7648d66790515c14d95d10a15bf3 (patch)
treef1a2f2c8cbcdcffac8bc6f05d17a8711f611aa96
parent58e1010da3c15e7bdf426b0a3d4b13dba1b7d055 (diff)
sched: fix minimum granularity tunings
increase the default minimum granularity some more - this gives us more performance in aim7 benchmarks. also correct some comments: we scale with ilog(ncpus) + 1. Signed-off-by: Zou Nan hai <nanhai.zou@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched_fair.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index ee00da284b1..2f16e15c022 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -22,7 +22,7 @@
/*
* Targeted preemption latency for CPU-bound tasks:
- * (default: 20ms * ilog(ncpus), units: nanoseconds)
+ * (default: 20ms * (1 + ilog(ncpus)), units: nanoseconds)
*
* NOTE: this latency value is not the same as the concept of
* 'timeslice length' - timeslices in CFS are of variable length
@@ -36,14 +36,14 @@ unsigned int sysctl_sched_latency = 20000000ULL;
/*
* Minimal preemption granularity for CPU-bound tasks:
- * (default: 1 msec * ilog(ncpus), units: nanoseconds)
+ * (default: 4 msec * (1 + ilog(ncpus)), units: nanoseconds)
*/
-unsigned int sysctl_sched_min_granularity = 1000000ULL;
+unsigned int sysctl_sched_min_granularity = 4000000ULL;
/*
* is kept at sysctl_sched_latency / sysctl_sched_min_granularity
*/
-static unsigned int sched_nr_latency = 20;
+static unsigned int sched_nr_latency = 5;
/*
* After fork, child runs first. (default) If set to 0 then
@@ -61,7 +61,7 @@ unsigned int __read_mostly sysctl_sched_compat_yield;
/*
* SCHED_BATCH wake-up granularity.
- * (default: 10 msec * ilog(ncpus), units: nanoseconds)
+ * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
*
* This option delays the preemption effects of decoupled workloads
* and reduces their over-scheduling. Synchronous workloads will still
@@ -71,7 +71,7 @@ unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL;
/*
* SCHED_OTHER wake-up granularity.
- * (default: 10 msec * ilog(ncpus), units: nanoseconds)
+ * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
*
* This option delays the preemption effects of decoupled workloads
* and reduces their over-scheduling. Synchronous workloads will still