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authorIngo Molnar <mingo@elte.hu>2007-08-09 11:16:52 +0200
committerIngo Molnar <mingo@elte.hu>2007-08-09 11:16:52 +0200
commit7cff8cf61cac15fa29a1ca802826d2bcbca66152 (patch)
tree86fa25bbf7d8cd3b23f7230fb821cdb04990ebfc /kernel/sched_fair.c
parenta69edb55605117cc0f20aa36c49c20b96590774d (diff)
downloadop-kernel-dev-7cff8cf61cac15fa29a1ca802826d2bcbca66152.zip
op-kernel-dev-7cff8cf61cac15fa29a1ca802826d2bcbca66152.tar.gz
sched: refine negative nice level granularity
refine the granularity of negative nice level tasks: let them reschedule more often to offset the effect of them consuming their wait_runtime proportionately slower. (This makes nice-0 task scheduling smoother in the presence of negatively reniced tasks.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r--kernel/sched_fair.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 7a632c5..e91db32 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -222,21 +222,25 @@ niced_granularity(struct sched_entity *curr, unsigned long granularity)
{
u64 tmp;
+ if (likely(curr->load.weight == NICE_0_LOAD))
+ return granularity;
/*
- * Negative nice levels get the same granularity as nice-0:
+ * Positive nice levels get the same granularity as nice-0:
*/
- if (likely(curr->load.weight >= NICE_0_LOAD))
- return granularity;
+ if (likely(curr->load.weight < NICE_0_LOAD)) {
+ tmp = curr->load.weight * (u64)granularity;
+ return (long) (tmp >> NICE_0_SHIFT);
+ }
/*
- * Positive nice level tasks get linearly finer
+ * Negative nice level tasks get linearly finer
* granularity:
*/
- tmp = curr->load.weight * (u64)granularity;
+ tmp = curr->load.inv_weight * (u64)granularity;
/*
* It will always fit into 'long':
*/
- return (long) (tmp >> NICE_0_SHIFT);
+ return (long) (tmp >> WMULT_SHIFT);
}
static inline void
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