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>
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 @@
{
u64 tmp;
- /*
- * Negative nice levels get the same granularity as nice-0:
- */
- if (likely(curr->load.weight >= NICE_0_LOAD))
+ if (likely(curr->load.weight == NICE_0_LOAD))
return granularity;
/*
- * Positive nice level tasks get linearly finer
+ * Positive nice levels get the same granularity as nice-0:
+ */
+ if (likely(curr->load.weight < NICE_0_LOAD)) {
+ tmp = curr->load.weight * (u64)granularity;
+ return (long) (tmp >> NICE_0_SHIFT);
+ }
+ /*
+ * 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