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[PATCH V4 4/6] Sched: Add scheduler stat for cpu time slice extension

Prakash Sangappa posted 6 patches 7 months, 1 week ago
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[PATCH V4 4/6] Sched: Add scheduler stat for cpu time slice extension
Posted by Prakash Sangappa 7 months, 1 week ago 
Add scheduler stat to record number of times the thread was granted
cpu time slice extension.

Signed-off-by: Prakash Sangappa <prakash.sangappa@oracle.com>
---
 include/linux/sched.h | 2 ++
 kernel/rseq.c         | 1 +
 kernel/sched/core.c   | 5 +++++
 kernel/sched/debug.c  | 1 +
 4 files changed, 9 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index c279232ca6a2..8cf756e80ae9 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -340,6 +340,7 @@ extern void io_schedule_finish(int token);
 extern long io_schedule_timeout(long timeout);
 extern void io_schedule(void);
 extern void hrtick_local_start(u64 delay);
+extern void update_stat_preempt_delayed(struct task_struct *t);
 
 /* wrapper function to trace from this header file */
 DECLARE_TRACEPOINT(sched_set_state_tp);
@@ -563,6 +564,7 @@ struct sched_statistics {
 	u64				nr_wakeups_affine_attempts;
 	u64				nr_wakeups_passive;
 	u64				nr_wakeups_idle;
+	u64				nr_preempt_delay_granted;
 
 #ifdef CONFIG_SCHED_CORE
 	u64				core_forceidle_sum;
diff --git a/kernel/rseq.c b/kernel/rseq.c
index 44d0f3ae0cd3..c4bc52f8ba9c 100644
--- a/kernel/rseq.c
+++ b/kernel/rseq.c
@@ -475,6 +475,7 @@ bool rseq_delay_resched(void)
 		return false;
 
 	t->sched_time_delay = 1;
+	update_stat_preempt_delayed(t);
 
 	return true;
 }
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 31928cbcd907..880368756b48 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -938,6 +938,11 @@ void hrtick_local_start(u64 delay)
 	rq_unlock(rq, &rf);
 }
 
+void update_stat_preempt_delayed(struct task_struct *t)
+{
+	schedstat_inc(t->stats.nr_preempt_delay_granted);
+}
+
 static void hrtick_rq_init(struct rq *rq)
 {
 #ifdef CONFIG_SMP
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 4cba21f5d24d..6b753f56c312 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -1216,6 +1216,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
 		P_SCHEDSTAT(nr_wakeups_affine_attempts);
 		P_SCHEDSTAT(nr_wakeups_passive);
 		P_SCHEDSTAT(nr_wakeups_idle);
+		P_SCHEDSTAT(nr_preempt_delay_granted);
 
 		avg_atom = p->se.sum_exec_runtime;
 		if (nr_switches)
-- 
2.43.5
Re: [PATCH V4 4/6] Sched: Add scheduler stat for cpu time slice extension
Posted by Madadi Vineeth Reddy 7 months, 1 week ago 
On 14/05/25 03:15, Prakash Sangappa wrote:
> Add scheduler stat to record number of times the thread was granted
> cpu time slice extension.
> 
> Signed-off-by: Prakash Sangappa <prakash.sangappa@oracle.com>
> ---
>  include/linux/sched.h | 2 ++
>  kernel/rseq.c         | 1 +
>  kernel/sched/core.c   | 5 +++++
>  kernel/sched/debug.c  | 1 +
>  4 files changed, 9 insertions(+)
> 
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index c279232ca6a2..8cf756e80ae9 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -340,6 +340,7 @@ extern void io_schedule_finish(int token);
>  extern long io_schedule_timeout(long timeout);
>  extern void io_schedule(void);
>  extern void hrtick_local_start(u64 delay);
> +extern void update_stat_preempt_delayed(struct task_struct *t);
>  
>  /* wrapper function to trace from this header file */
>  DECLARE_TRACEPOINT(sched_set_state_tp);
> @@ -563,6 +564,7 @@ struct sched_statistics {
>  	u64				nr_wakeups_affine_attempts;
>  	u64				nr_wakeups_passive;
>  	u64				nr_wakeups_idle;
> +	u64				nr_preempt_delay_granted;
>  
>  #ifdef CONFIG_SCHED_CORE
>  	u64				core_forceidle_sum;
> diff --git a/kernel/rseq.c b/kernel/rseq.c
> index 44d0f3ae0cd3..c4bc52f8ba9c 100644
> --- a/kernel/rseq.c
> +++ b/kernel/rseq.c
> @@ -475,6 +475,7 @@ bool rseq_delay_resched(void)
>  		return false;
>  
>  	t->sched_time_delay = 1;
> +	update_stat_preempt_delayed(t);
>  
>  	return true;
>  }
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 31928cbcd907..880368756b48 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -938,6 +938,11 @@ void hrtick_local_start(u64 delay)
>  	rq_unlock(rq, &rf);
>  }
>  
> +void update_stat_preempt_delayed(struct task_struct *t)
> +{
> +	schedstat_inc(t->stats.nr_preempt_delay_granted);

I think schedstat documentation also needs to be updated
and may be bump the version number.

Thanks,
Madadi Vineeth Reddy

> +}
> +
>  static void hrtick_rq_init(struct rq *rq)
>  {
>  #ifdef CONFIG_SMP
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 4cba21f5d24d..6b753f56c312 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -1216,6 +1216,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
>  		P_SCHEDSTAT(nr_wakeups_affine_attempts);
>  		P_SCHEDSTAT(nr_wakeups_passive);
>  		P_SCHEDSTAT(nr_wakeups_idle);
> +		P_SCHEDSTAT(nr_preempt_delay_granted);
>  
>  		avg_atom = p->se.sum_exec_runtime;
>  		if (nr_switches)
Re: [PATCH V4 4/6] Sched: Add scheduler stat for cpu time slice extension
Posted by Prakash Sangappa 7 months, 1 week ago 

> On May 14, 2025, at 5:37 AM, Madadi Vineeth Reddy <vineethr@linux.ibm.com> wrote:
> 
> On 14/05/25 03:15, Prakash Sangappa wrote:
>> Add scheduler stat to record number of times the thread was granted
>> cpu time slice extension.
>> 
>> Signed-off-by: Prakash Sangappa <prakash.sangappa@oracle.com>
>> ---
>> include/linux/sched.h | 2 ++
>> kernel/rseq.c         | 1 +
>> kernel/sched/core.c   | 5 +++++
>> kernel/sched/debug.c  | 1 +
>> 4 files changed, 9 insertions(+)
>> 
>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>> index c279232ca6a2..8cf756e80ae9 100644
>> --- a/include/linux/sched.h
>> +++ b/include/linux/sched.h
>> @@ -340,6 +340,7 @@ extern void io_schedule_finish(int token);
>> extern long io_schedule_timeout(long timeout);
>> extern void io_schedule(void);
>> extern void hrtick_local_start(u64 delay);
>> +extern void update_stat_preempt_delayed(struct task_struct *t);
>> 
>> /* wrapper function to trace from this header file */
>> DECLARE_TRACEPOINT(sched_set_state_tp);
>> @@ -563,6 +564,7 @@ struct sched_statistics {
>> u64 nr_wakeups_affine_attempts;
>> u64 nr_wakeups_passive;
>> u64 nr_wakeups_idle;
>> + u64 nr_preempt_delay_granted;
>> 
>> #ifdef CONFIG_SCHED_CORE
>> u64 core_forceidle_sum;
>> diff --git a/kernel/rseq.c b/kernel/rseq.c
>> index 44d0f3ae0cd3..c4bc52f8ba9c 100644
>> --- a/kernel/rseq.c
>> +++ b/kernel/rseq.c
>> @@ -475,6 +475,7 @@ bool rseq_delay_resched(void)
>> return false;
>> 
>> t->sched_time_delay = 1;
>> + update_stat_preempt_delayed(t);
>> 
>> return true;
>> }
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index 31928cbcd907..880368756b48 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -938,6 +938,11 @@ void hrtick_local_start(u64 delay)
>> rq_unlock(rq, &rf);
>> }
>> 
>> +void update_stat_preempt_delayed(struct task_struct *t)
>> +{
>> + schedstat_inc(t->stats.nr_preempt_delay_granted);
> 
> I think schedstat documentation also needs to be updated
> and may be bump the version number.


Will update documentation. 

-Prakash

> 
> Thanks,
> Madadi Vineeth Reddy
> 
>> +}
>> +
>> static void hrtick_rq_init(struct rq *rq)
>> {
>> #ifdef CONFIG_SMP
>> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
>> index 4cba21f5d24d..6b753f56c312 100644
>> --- a/kernel/sched/debug.c
>> +++ b/kernel/sched/debug.c
>> @@ -1216,6 +1216,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
>> P_SCHEDSTAT(nr_wakeups_affine_attempts);
>> P_SCHEDSTAT(nr_wakeups_passive);
>> P_SCHEDSTAT(nr_wakeups_idle);
>> + P_SCHEDSTAT(nr_preempt_delay_granted);
>> 
>> avg_atom = p->se.sum_exec_runtime;
>> if (nr_switches)
>

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