The following commit has been merged into the sched/core branch of tip:
Commit-ID: e0c2ff903c320d3fd3c2c604dc401b3b7c0a1d13
Gitweb: https://git.kernel.org/tip/e0c2ff903c320d3fd3c2c604dc401b3b7c0a1d13
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 31 May 2023 13:58:41 +02:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 19 Jul 2023 09:43:58 +02:00
sched/fair: Remove sched_feat(START_DEBIT)
With the introduction of avg_vruntime() there is no need to use worse
approximations. Take the 0-lag point as starting point for inserting
new tasks.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230531124603.722361178@xxxxxxxxxxxxx
---
kernel/sched/fair.c | 21 +--------------------
kernel/sched/features.h | 6 ------
2 files changed, 1 insertion(+), 26 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bb54606..fc43482 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -906,16 +906,6 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
return slice;
}
-/*
- * We calculate the vruntime slice of a to-be-inserted task.
- *
- * vs = s/w
- */
-static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- return calc_delta_fair(sched_slice(cfs_rq, se), se);
-}
-
#include "pelt.h"
#ifdef CONFIG_SMP
@@ -4862,16 +4852,7 @@ static inline bool entity_is_long_sleeper(struct sched_entity *se)
static void
place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
{
- u64 vruntime = cfs_rq->min_vruntime;
-
- /*
- * The 'current' period is already promised to the current tasks,
- * however the extra weight of the new task will slow them down a
- * little, place the new task so that it fits in the slot that
- * stays open at the end.
- */
- if (initial && sched_feat(START_DEBIT))
- vruntime += sched_vslice(cfs_rq, se);
+ u64 vruntime = avg_vruntime(cfs_rq);
/* sleeps up to a single latency don't count. */
if (!initial) {
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index ee7f23c..fa828b3 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -7,12 +7,6 @@
SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
/*
- * Place new tasks ahead so that they do not starve already running
- * tasks
- */
-SCHED_FEAT(START_DEBIT, true)
-
-/*
* Prefer to schedule the task we woke last (assuming it failed
* wakeup-preemption), since its likely going to consume data we
* touched, increases cache locality.
|