[PATCH] sched/fair: remove the DOUBLE_TICK feature

[PATCH] sched/fair: remove the DOUBLE_TICK feature

[Huang Shijie]

The patch "5e963f2bd46 sched/fair: Commit to EEVDF"
removed the code following the DOUBLE_TICK:
	-
	-       if (!sched_feat(EEVDF) && cfs_rq->nr_running > 1)
	-               check_preempt_tick(cfs_rq, curr);

The DOUBLE_TICK feature becomes dead code now, so remove it.

Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com>
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
---
 kernel/sched/fair.c     | 6 ------
 kernel/sched/features.h | 1 -
 2 files changed, 7 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 19afc2253c4d..1812c9cc079d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5680,12 +5680,6 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 		resched_curr(rq_of(cfs_rq));
 		return;
 	}
-	/*
-	 * don't let the period tick interfere with the hrtick preemption
-	 */
-	if (!sched_feat(DOUBLE_TICK) &&
-			hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
-		return;
 #endif
 }
 
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 0ae351974e49..a3d331dd2d8f 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -56,7 +56,6 @@ SCHED_FEAT(WAKEUP_PREEMPTION, true)
 
 SCHED_FEAT(HRTICK, false)
 SCHED_FEAT(HRTICK_DL, false)
-SCHED_FEAT(DOUBLE_TICK, false)
 
 /*
  * Decrement CPU capacity based on time not spent running tasks
-- 
2.40.1

Re: [PATCH] sched/fair: remove the DOUBLE_TICK feature

[Vishal Chourasia]

On Tue, Oct 01, 2024 at 02:54:51PM +0800, Huang Shijie wrote:
> The patch "5e963f2bd46 sched/fair: Commit to EEVDF"
> removed the code following the DOUBLE_TICK:
> 	-
> 	-       if (!sched_feat(EEVDF) && cfs_rq->nr_running > 1)
> 	-               check_preempt_tick(cfs_rq, curr);
> 
> The DOUBLE_TICK feature becomes dead code now, so remove it.
> 
> Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com>
> Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>

Reviewed-by: Vishal Chourasia <vishalc@linux.ibm.com>

[1] https://lore.kernel.org/all/20240308052304.1835792-2-vishalc@linux.ibm.com
> ---
>  kernel/sched/fair.c     | 6 ------
>  kernel/sched/features.h | 1 -
>  2 files changed, 7 deletions(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 19afc2253c4d..1812c9cc079d 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5680,12 +5680,6 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
>  		resched_curr(rq_of(cfs_rq));
>  		return;
>  	}
> -	/*
> -	 * don't let the period tick interfere with the hrtick preemption
> -	 */
> -	if (!sched_feat(DOUBLE_TICK) &&
> -			hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
> -		return;
>  #endif
>  }
>  
> diff --git a/kernel/sched/features.h b/kernel/sched/features.h
> index 0ae351974e49..a3d331dd2d8f 100644
> --- a/kernel/sched/features.h
> +++ b/kernel/sched/features.h
> @@ -56,7 +56,6 @@ SCHED_FEAT(WAKEUP_PREEMPTION, true)
>  
>  SCHED_FEAT(HRTICK, false)
>  SCHED_FEAT(HRTICK_DL, false)
> -SCHED_FEAT(DOUBLE_TICK, false)
>  
>  /*
>   * Decrement CPU capacity based on time not spent running tasks
> -- 
> 2.40.1
> 

[tip: sched/core] sched/fair: remove the DOUBLE_TICK feature

[tip-bot2 for Huang Shijie]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     e31488c9df27aaea2cdffba688129fdeb3869650
Gitweb:        https://git.kernel.org/tip/e31488c9df27aaea2cdffba688129fdeb3869650
Author:        Huang Shijie <shijie@os.amperecomputing.com>
AuthorDate:    Tue, 01 Oct 2024 14:54:51 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 07 Oct 2024 09:28:40 +02:00

sched/fair: remove the DOUBLE_TICK feature

The patch "5e963f2bd46 sched/fair: Commit to EEVDF"
removed the code following the DOUBLE_TICK:
	-
	-       if (!sched_feat(EEVDF) && cfs_rq->nr_running > 1)
	-               check_preempt_tick(cfs_rq, curr);

The DOUBLE_TICK feature becomes dead code now, so remove it.

Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: "Christoph Lameter (Ampere)" <cl@linux.com>
Reviewed-by: Vishal Chourasia <vishalc@linux.ibm.com>
Link: https://lore.kernel.org/r/20241001065451.10356-1-shijie@os.amperecomputing.com
---
 kernel/sched/fair.c     | 6 ------
 kernel/sched/features.h | 1 -
 2 files changed, 7 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 225b31a..c9e3b8d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5680,12 +5680,6 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 		resched_curr(rq_of(cfs_rq));
 		return;
 	}
-	/*
-	 * don't let the period tick interfere with the hrtick preemption
-	 */
-	if (!sched_feat(DOUBLE_TICK) &&
-			hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
-		return;
 #endif
 }
 
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 2908740..7c22b33 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -56,7 +56,6 @@ SCHED_FEAT(WAKEUP_PREEMPTION, true)
 
 SCHED_FEAT(HRTICK, false)
 SCHED_FEAT(HRTICK_DL, false)
-SCHED_FEAT(DOUBLE_TICK, false)
 
 /*
  * Decrement CPU capacity based on time not spent running tasks