From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, vincent.guittot@linaro.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
juri.lelli@redhat.com, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, corbet@lwn.net, qyousef@layalina.io,
chris.hyser@oracle.com, patrick.bellasi@matbug.net,
pjt@google.com, pavel@ucw.cz, qperret@google.com,
tim.c.chen@linux.intel.com, joshdon@google.com, timj@gnu.org,
kprateek.nayak@amd.com, yu.c.chen@intel.com,
youssefesmat@chromium.org, joel@joelfernandes.org
Subject: [PATCH 07/10] sched/fair: Remove START_DEBIT
Date: Mon, 06 Mar 2023 14:25:28 +0100 [thread overview]
Message-ID: <20230306141502.630872931@infradead.org> (raw)
In-Reply-To: 20230306132521.968182689@infradead.org
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@infradead.org>
---
kernel/sched/fair.c | 21 +--------------------
kernel/sched/features.h | 6 ------
2 files changed, 1 insertion(+), 26 deletions(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -882,16 +882,6 @@ static u64 sched_slice(struct cfs_rq *cf
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
@@ -4758,18 +4748,9 @@ static void check_spread(struct cfs_rq *
static void
place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
{
- u64 vruntime = cfs_rq->min_vruntime;
+ u64 vruntime = avg_vruntime(cfs_rq);
u64 sleep_time;
- /*
- * 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);
-
/* sleeps up to a single latency don't count. */
if (!initial) {
unsigned long thresh;
--- 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.
next prev parent reply other threads:[~2023-03-06 14:20 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-06 13:25 [PATCH 00/10] sched: EEVDF using latency-nice Peter Zijlstra
2023-03-06 13:25 ` [PATCH 01/10] sched: Introduce latency-nice as a per-task attribute Peter Zijlstra
2023-03-06 13:25 ` [PATCH 02/10] sched/core: Propagate parent tasks latency requirements to the child task Peter Zijlstra
2023-03-06 13:25 ` [PATCH 03/10] sched: Allow sched_{get,set}attr to change latency_nice of the task Peter Zijlstra
2023-03-06 13:25 ` [PATCH 04/10] sched/fair: Add latency_offset Peter Zijlstra
2023-03-06 13:25 ` [PATCH 05/10] sched/fair: Add sched group latency support Peter Zijlstra
2023-03-06 13:25 ` [PATCH 06/10] sched/fair: Add avg_vruntime Peter Zijlstra
2023-03-21 13:58 ` Chen Yu
2023-03-21 16:04 ` Peter Zijlstra
2023-03-24 7:12 ` Chen Yu
2023-03-24 10:03 ` Peter Zijlstra
2023-03-06 13:25 ` Peter Zijlstra [this message]
2023-03-06 13:25 ` [PATCH 08/10] sched/fair: Add lag based placement Peter Zijlstra
2023-03-16 22:49 ` Tim Chen
2023-03-06 13:25 ` [PATCH 09/10] rbtree: Add rb_add_augmented_cached() helper Peter Zijlstra
2023-03-06 13:25 ` [PATCH 10/10] sched/fair: Implement an EEVDF like policy Peter Zijlstra
2023-03-08 8:39 ` Mike Galbraith
2023-03-08 9:26 ` Mike Galbraith
2023-03-08 13:36 ` Mike Galbraith
2023-03-09 4:23 ` Mike Galbraith
2023-03-10 20:38 ` Peter Zijlstra
2023-03-11 5:53 ` Mike Galbraith
2023-03-11 7:56 ` Mike Galbraith
2023-03-09 9:06 ` Peter Zijlstra
2023-03-09 12:44 ` Peter Zijlstra
2023-03-09 15:29 ` Peter Zijlstra
2023-03-09 15:39 ` Peter Zijlstra
2023-03-09 16:24 ` Mike Galbraith
2023-03-09 16:42 ` Peter Zijlstra
2023-03-07 10:27 ` [PATCH 00/10] sched: EEVDF using latency-nice Vincent Guittot
2023-03-07 13:08 ` Peter Zijlstra
2023-03-08 15:13 ` Shrikanth Hegde
2023-03-22 6:49 ` K Prateek Nayak
2023-03-22 9:38 ` K Prateek Nayak
2023-03-23 11:53 ` Pavel Machek
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