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Commit 7cff8cf6 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

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: default avatarIngo Molnar <mingo@elte.hu>
parent a69edb55

kernel/sched_fair.c

+10 −6
Original line number Diff line number Diff line
@@ -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