[v2] sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec_clock

[PATCH v2] sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec_clock

Posted by Chuyi Zhou 1 year, 5 months ago

nr_spread_over tracks the number of instances where the difference
between a scheduling entity's virtual runtime and the minimum virtual
runtime in the runqueue exceeds three times the scheduler latency,
indicating significant disparity in task scheduling.
Commit that removed its usage: 5e963f2bd: sched/fair: Commit to EEVDF

cfs_rq->exec_clock was used to account for time spent executing tasks.
Commit that removed its usage: 5d69eca542ee1 sched: Unify runtime
accounting across classes

cfs_rq::nr_spread_over and cfs_rq::exec_clock are not used anymore in
eevdf. Remove them from struct cfs_rq.

Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Acked-by: Vishal Chourasia <vishalc@linux.ibm.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
---
 kernel/sched/debug.c | 4 ----
 kernel/sched/sched.h | 6 ------
 2 files changed, 10 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index c1eb9a1afd13..90c4a9998377 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -641,8 +641,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 	SEQ_printf(m, "\n");
 	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
 #endif
-	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
-			SPLIT_NS(cfs_rq->exec_clock));
 
 	raw_spin_rq_lock_irqsave(rq, flags);
 	root = __pick_root_entity(cfs_rq);
@@ -669,8 +667,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 			SPLIT_NS(right_vruntime));
 	spread = right_vruntime - left_vruntime;
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
-	SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
-			cfs_rq->nr_spread_over);
 	SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
 	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
 	SEQ_printf(m, "  .%-30s: %d\n", "idle_nr_running",
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 4c36cc680361..8a071022bdec 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -599,7 +599,6 @@ struct cfs_rq {
 	s64			avg_vruntime;
 	u64			avg_load;
 
-	u64			exec_clock;
 	u64			min_vruntime;
 #ifdef CONFIG_SCHED_CORE
 	unsigned int		forceidle_seq;
@@ -619,10 +618,6 @@ struct cfs_rq {
 	struct sched_entity	*curr;
 	struct sched_entity	*next;
 
-#ifdef	CONFIG_SCHED_DEBUG
-	unsigned int		nr_spread_over;
-#endif
-
 #ifdef CONFIG_SMP
 	/*
 	 * CFS load tracking
@@ -1158,7 +1153,6 @@ struct rq {
 	/* latency stats */
 	struct sched_info	rq_sched_info;
 	unsigned long long	rq_cpu_time;
-	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
 
 	/* sys_sched_yield() stats */
 	unsigned int		yld_count;
-- 
2.20.1

Re: [PATCH v2] sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec_clock

Posted by K Prateek Nayak 1 year, 5 months ago

Hello Chuyi,

On 7/17/2024 8:03 PM, Chuyi Zhou wrote:
> nr_spread_over tracks the number of instances where the difference
> between a scheduling entity's virtual runtime and the minimum virtual
> runtime in the runqueue exceeds three times the scheduler latency,
> indicating significant disparity in task scheduling.
> Commit that removed its usage: 5e963f2bd: sched/fair: Commit to EEVDF

scripts/checkpatch.pl complains about the commit description style here.
The above can be reworded as:

Commit 5e963f2bd465 ("sched/fair: Commit to EEVDF") removed its usage.

> 
> cfs_rq->exec_clock was used to account for time spent executing tasks.
> Commit that removed its usage: 5d69eca542ee1 sched: Unify runtime
> accounting across classes

And this as:

Commit 5d69eca542ee ("sched: Unify runtime accounting across classes")
removed its usage.

> 
> cfs_rq::nr_spread_over and cfs_rq::exec_clock are not used anymore in
> eevdf. Remove them from struct cfs_rq.
> 
> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
> Acked-by: Vishal Chourasia <vishalc@linux.ibm.com>
> Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>

Apart from those nits,

Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>

-- 
Thanks and Regards,
Prateek

> ---
>   kernel/sched/debug.c | 4 ----
>   kernel/sched/sched.h | 6 ------
>   2 files changed, 10 deletions(-)
> 
> [..snip..]

Re: [PATCH v2] sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec_clock

Posted by Chuyi Zhou 1 year, 5 months ago

Hello,

在 2024/7/18 11:28, K Prateek Nayak 写道:
> Hello Chuyi,
> 
> On 7/17/2024 8:03 PM, Chuyi Zhou wrote:
>> nr_spread_over tracks the number of instances where the difference
>> between a scheduling entity's virtual runtime and the minimum virtual
>> runtime in the runqueue exceeds three times the scheduler latency,
>> indicating significant disparity in task scheduling.
>> Commit that removed its usage: 5e963f2bd: sched/fair: Commit to EEVDF
> 
> scripts/checkpatch.pl complains about the commit description style here.
> The above can be reworded as:
> 

I will send v3 later.

Thanks for the review!

[tip: sched/core] sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec_clock

Posted by tip-bot2 for Chuyi Zhou 1 year, 4 months ago

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

Commit-ID:     2c2d9624697fc5e7dd84490ae01b80cc43ec2def
Gitweb:        https://git.kernel.org/tip/2c2d9624697fc5e7dd84490ae01b80cc43ec2def
Author:        Chuyi Zhou <zhouchuyi@bytedance.com>
AuthorDate:    Wed, 17 Jul 2024 22:33:42 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 29 Jul 2024 12:22:34 +02:00

sched/fair: Remove cfs_rq::nr_spread_over and cfs_rq::exec_clock

nr_spread_over tracks the number of instances where the difference
between a scheduling entity's virtual runtime and the minimum virtual
runtime in the runqueue exceeds three times the scheduler latency,
indicating significant disparity in task scheduling.
Commit that removed its usage: 5e963f2bd: sched/fair: Commit to EEVDF

cfs_rq->exec_clock was used to account for time spent executing tasks.
Commit that removed its usage: 5d69eca542ee1 sched: Unify runtime
accounting across classes

cfs_rq::nr_spread_over and cfs_rq::exec_clock are not used anymore in
eevdf. Remove them from struct cfs_rq.

Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Acked-by: Vishal Chourasia <vishalc@linux.ibm.com>
Link: https://lore.kernel.org/r/20240717143342.593262-1-zhouchuyi@bytedance.com
---
 kernel/sched/debug.c | 4 ----
 kernel/sched/sched.h | 6 ------
 2 files changed, 10 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index c1eb9a1..90c4a99 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -641,8 +641,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 	SEQ_printf(m, "\n");
 	SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
 #endif
-	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "exec_clock",
-			SPLIT_NS(cfs_rq->exec_clock));
 
 	raw_spin_rq_lock_irqsave(rq, flags);
 	root = __pick_root_entity(cfs_rq);
@@ -669,8 +667,6 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 			SPLIT_NS(right_vruntime));
 	spread = right_vruntime - left_vruntime;
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
-	SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
-			cfs_rq->nr_spread_over);
 	SEQ_printf(m, "  .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
 	SEQ_printf(m, "  .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
 	SEQ_printf(m, "  .%-30s: %d\n", "idle_nr_running",
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 4c36cc6..8a07102 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -599,7 +599,6 @@ struct cfs_rq {
 	s64			avg_vruntime;
 	u64			avg_load;
 
-	u64			exec_clock;
 	u64			min_vruntime;
 #ifdef CONFIG_SCHED_CORE
 	unsigned int		forceidle_seq;
@@ -619,10 +618,6 @@ struct cfs_rq {
 	struct sched_entity	*curr;
 	struct sched_entity	*next;
 
-#ifdef	CONFIG_SCHED_DEBUG
-	unsigned int		nr_spread_over;
-#endif
-
 #ifdef CONFIG_SMP
 	/*
 	 * CFS load tracking
@@ -1158,7 +1153,6 @@ struct rq {
 	/* latency stats */
 	struct sched_info	rq_sched_info;
 	unsigned long long	rq_cpu_time;
-	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
 
 	/* sys_sched_yield() stats */
 	unsigned int		yld_count;