diff mbox series

[v2] sched/freq: move call to cpufreq_update_util

Message ID 1573570093-1340-1-git-send-email-vincent.guittot@linaro.org
State New
Headers show
Series [v2] sched/freq: move call to cpufreq_update_util | expand

Commit Message

Vincent Guittot Nov. 12, 2019, 2:48 p.m. UTC
update_cfs_rq_load_avg() calls cfs_rq_util_change() everytime pelt decays,
which might be inefficient when cpufreq driver has rate limitation.

When a task is attached on a CPU, we have call path:

update_blocked_averages()
  update_cfs_rq_load_avg()
    cfs_rq_util_change -- > trig frequency update
  attach_entity_load_avg()
    cfs_rq_util_change -- > trig frequency update

The 1st frequency update will not take into account the utilization of the
newly attached task and the 2nd one might be discard because of rate
limitation of the cpufreq driver.

update_cfs_rq_load_avg() is only called by update_blocked_averages()
and update_load_avg() so we can move the call to
{cfs_rq,cpufreq}_util_change() into these 2 functions. It's also
interesting to notice that update_load_avg() already calls directly
cfs_rq_util_change() for !SMP case.

This changes will also ensure that cpufreq_update_util() is called even
when there is no more CFS rq in the leaf_cfs_rq_list to update but only
irq, rt or dl pelt signals.

Reported-by: Doug Smythies <dsmythies@telus.net>
Fixes: 039ae8bcf7a5 ("sched/fair: Fix O(nr_cgroups) in the load balancing path")
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>


---

I have just rebased the patch on latest tip/sched/core and made it a proper
patchset after Doug reported that the problem has diseappeared according to
his 1st results but tests results are not all based on the same v5.4-rcX
and with menu instead of teo governor.

 kernel/sched/fair.c | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

-- 
2.7.4

Comments

Vincent Guittot Nov. 12, 2019, 3:05 p.m. UTC | #1
Le Tuesday 12 Nov 2019 à 15:48:13 (+0100), Vincent Guittot a écrit :
> update_cfs_rq_load_avg() calls cfs_rq_util_change() everytime pelt decays,

> which might be inefficient when cpufreq driver has rate limitation.

> 

> When a task is attached on a CPU, we have call path:

> 

> update_blocked_averages()

>   update_cfs_rq_load_avg()

>     cfs_rq_util_change -- > trig frequency update

>   attach_entity_load_avg()

>     cfs_rq_util_change -- > trig frequency update

> 

> The 1st frequency update will not take into account the utilization of the

> newly attached task and the 2nd one might be discard because of rate

> limitation of the cpufreq driver.

> 

> update_cfs_rq_load_avg() is only called by update_blocked_averages()

> and update_load_avg() so we can move the call to

> {cfs_rq,cpufreq}_util_change() into these 2 functions. It's also

> interesting to notice that update_load_avg() already calls directly

> cfs_rq_util_change() for !SMP case.

> 

> This changes will also ensure that cpufreq_update_util() is called even

> when there is no more CFS rq in the leaf_cfs_rq_list to update but only

> irq, rt or dl pelt signals.

> 

> Reported-by: Doug Smythies <dsmythies@telus.net>

> Fixes: 039ae8bcf7a5 ("sched/fair: Fix O(nr_cgroups) in the load balancing path")

> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

> 

> ---

> 

> I have just rebased the patch on latest tip/sched/core and made it a proper

> patchset after Doug reported that the problem has diseappeared according to

> his 1st results but tests results are not all based on the same v5.4-rcX

> and with menu instead of teo governor.

> 

>  kernel/sched/fair.c | 33 +++++++++++++++++++++------------

>  1 file changed, 21 insertions(+), 12 deletions(-)

> 

> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c

> index e458f52..c93d534 100644

> --- a/kernel/sched/fair.c

> +++ b/kernel/sched/fair.c

> @@ -3508,9 +3508,6 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)

>  	cfs_rq->load_last_update_time_copy = sa->last_update_time;

>  #endif

>  

> -	if (decayed)

> -		cfs_rq_util_change(cfs_rq, 0);

> -

>  	return decayed;

>  }

>  

> @@ -3620,8 +3617,12 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s

>  		attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION);

>  		update_tg_load_avg(cfs_rq, 0);

>  

> -	} else if (decayed && (flags & UPDATE_TG))

> -		update_tg_load_avg(cfs_rq, 0);

> +	} else if (decayed) {

> +		cfs_rq_util_change(cfs_rq, 0);

> +

> +		if (flags & UPDATE_TG)

> +			update_tg_load_avg(cfs_rq, 0);

> +	}

>  }

>  

>  #ifndef CONFIG_64BIT

> @@ -7484,6 +7485,7 @@ static void update_blocked_averages(int cpu)

>  	const struct sched_class *curr_class;

>  	struct rq_flags rf;

>  	bool done = true;

> +	int decayed = 0;

>  

>  	rq_lock_irqsave(rq, &rf);

>  	update_rq_clock(rq);

> @@ -7493,9 +7495,9 @@ static void update_blocked_averages(int cpu)

>  	 * that RT, DL and IRQ signals have been updated before updating CFS.

>  	 */

>  	curr_class = rq->curr->sched_class;

> -	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> -	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> -	update_irq_load_avg(rq, 0);

> +	decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> +	decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> +	decayed |= update_irq_load_avg(rq, 0);

>  

>  	/* Don't need periodic decay once load/util_avg are null */

>  	if (others_have_blocked(rq))

> @@ -7529,6 +7531,9 @@ static void update_blocked_averages(int cpu)

>  	}

>  

>  	update_blocked_load_status(rq, !done);

> +

> +	if (decayed)

> +		cpufreq_update_util(rq, 0);

>  	rq_unlock_irqrestore(rq, &rf);

>  }

>  

> @@ -7585,6 +7590,7 @@ static inline void update_blocked_averages(int cpu)

>  	struct cfs_rq *cfs_rq = &rq->cfs;

>  	const struct sched_class *curr_class;

>  	struct rq_flags rf;

> +	int decayed = 0;

>  

>  	rq_lock_irqsave(rq, &rf);

>  	update_rq_clock(rq);

> @@ -7594,13 +7600,16 @@ static inline void update_blocked_averages(int cpu)

>  	 * that RT, DL and IRQ signals have been updated before updating CFS.

>  	 */

>  	curr_class = rq->curr->sched_class;

> -	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> -	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> -	update_irq_load_avg(rq, 0);

> +	decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> +	decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> +	decayed |= update_irq_load_avg(rq, 0);

>  

> -	update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);

> +	decayed |= update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);

>  

>  	update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq));

> +

> +	if (decayed)

> +		cpufreq_update_util(rq, 0);

>  	rq_unlock_irqrestore(rq, &rf);

>  }

>  

> -- 

> 2.7.4

>
Vincent Guittot Nov. 12, 2019, 5:20 p.m. UTC | #2
On Tue, 12 Nov 2019 at 18:11, Valentin Schneider
<valentin.schneider@arm.com> wrote:
>

> Hi Vincent,

>

> I didn't see anything in that reply, was that just a spurious email?


there were a typo in one email address in the 1st message

>

> On 12/11/2019 15:05, Vincent Guittot wrote:

> > Le Tuesday 12 Nov 2019 à 15:48:13 (+0100), Vincent Guittot a écrit :

> >> update_cfs_rq_load_avg() calls cfs_rq_util_change() everytime pelt decays,

> >> which might be inefficient when cpufreq driver has rate limitation.

> >>

> >> When a task is attached on a CPU, we have call path:

> >>

> >> update_blocked_averages()

> >>   update_cfs_rq_load_avg()

> >>     cfs_rq_util_change -- > trig frequency update

> >>   attach_entity_load_avg()

> >>     cfs_rq_util_change -- > trig frequency update

> >>

> >> The 1st frequency update will not take into account the utilization of the

> >> newly attached task and the 2nd one might be discard because of rate

> >> limitation of the cpufreq driver.

> >>

> >> update_cfs_rq_load_avg() is only called by update_blocked_averages()

> >> and update_load_avg() so we can move the call to

> >> {cfs_rq,cpufreq}_util_change() into these 2 functions. It's also

> >> interesting to notice that update_load_avg() already calls directly

> >> cfs_rq_util_change() for !SMP case.

> >>

> >> This changes will also ensure that cpufreq_update_util() is called even

> >> when there is no more CFS rq in the leaf_cfs_rq_list to update but only

> >> irq, rt or dl pelt signals.

> >>

> >> Reported-by: Doug Smythies <dsmythies@telus.net>

> >> Fixes: 039ae8bcf7a5 ("sched/fair: Fix O(nr_cgroups) in the load balancing path")

> >> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

> >>

> >> ---

> >>

> >> I have just rebased the patch on latest tip/sched/core and made it a proper

> >> patchset after Doug reported that the problem has diseappeared according to

> >> his 1st results but tests results are not all based on the same v5.4-rcX

> >> and with menu instead of teo governor.

> >>

> >>  kernel/sched/fair.c | 33 +++++++++++++++++++++------------

> >>  1 file changed, 21 insertions(+), 12 deletions(-)

> >>

> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c

> >> index e458f52..c93d534 100644

> >> --- a/kernel/sched/fair.c

> >> +++ b/kernel/sched/fair.c

> >> @@ -3508,9 +3508,6 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)

> >>      cfs_rq->load_last_update_time_copy = sa->last_update_time;

> >>  #endif

> >>

> >> -    if (decayed)

> >> -            cfs_rq_util_change(cfs_rq, 0);

> >> -

> >>      return decayed;

> >>  }

> >>

> >> @@ -3620,8 +3617,12 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s

> >>              attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION);

> >>              update_tg_load_avg(cfs_rq, 0);

> >>

> >> -    } else if (decayed && (flags & UPDATE_TG))

> >> -            update_tg_load_avg(cfs_rq, 0);

> >> +    } else if (decayed) {

> >> +            cfs_rq_util_change(cfs_rq, 0);

> >> +

> >> +            if (flags & UPDATE_TG)

> >> +                    update_tg_load_avg(cfs_rq, 0);

> >> +    }

> >>  }

> >>

> >>  #ifndef CONFIG_64BIT

> >> @@ -7484,6 +7485,7 @@ static void update_blocked_averages(int cpu)

> >>      const struct sched_class *curr_class;

> >>      struct rq_flags rf;

> >>      bool done = true;

> >> +    int decayed = 0;

> >>

> >>      rq_lock_irqsave(rq, &rf);

> >>      update_rq_clock(rq);

> >> @@ -7493,9 +7495,9 @@ static void update_blocked_averages(int cpu)

> >>       * that RT, DL and IRQ signals have been updated before updating CFS.

> >>       */

> >>      curr_class = rq->curr->sched_class;

> >> -    update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> >> -    update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> >> -    update_irq_load_avg(rq, 0);

> >> +    decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> >> +    decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> >> +    decayed |= update_irq_load_avg(rq, 0);

> >>

> >>      /* Don't need periodic decay once load/util_avg are null */

> >>      if (others_have_blocked(rq))

> >> @@ -7529,6 +7531,9 @@ static void update_blocked_averages(int cpu)

> >>      }

> >>

> >>      update_blocked_load_status(rq, !done);

> >> +

> >> +    if (decayed)

> >> +            cpufreq_update_util(rq, 0);

> >>      rq_unlock_irqrestore(rq, &rf);

> >>  }

> >>

> >> @@ -7585,6 +7590,7 @@ static inline void update_blocked_averages(int cpu)

> >>      struct cfs_rq *cfs_rq = &rq->cfs;

> >>      const struct sched_class *curr_class;

> >>      struct rq_flags rf;

> >> +    int decayed = 0;

> >>

> >>      rq_lock_irqsave(rq, &rf);

> >>      update_rq_clock(rq);

> >> @@ -7594,13 +7600,16 @@ static inline void update_blocked_averages(int cpu)

> >>       * that RT, DL and IRQ signals have been updated before updating CFS.

> >>       */

> >>      curr_class = rq->curr->sched_class;

> >> -    update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> >> -    update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> >> -    update_irq_load_avg(rq, 0);

> >> +    decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> >> +    decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> >> +    decayed |= update_irq_load_avg(rq, 0);

> >>

> >> -    update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);

> >> +    decayed |= update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);

> >>

> >>      update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq));

> >> +

> >> +    if (decayed)

> >> +            cpufreq_update_util(rq, 0);

> >>      rq_unlock_irqrestore(rq, &rf);

> >>  }

> >>

> >> --

> >> 2.7.4

> >>
Vincent Guittot Nov. 13, 2019, 5:50 p.m. UTC | #3
Le Wednesday 13 Nov 2019 à 15:09:47 (+0100), Dietmar Eggemann a écrit :
> On 13.11.19 14:30, Vincent Guittot wrote:

> > On Wed, 13 Nov 2019 at 11:50, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:

> >>

> >> On 12.11.19 16:05, Vincent Guittot wrote:

> >>> Le Tuesday 12 Nov 2019 à 15:48:13 (+0100), Vincent Guittot a écrit :

> 

> [...]

> 

> >>>> @@ -7493,9 +7495,9 @@ static void update_blocked_averages(int cpu)

> >>>>       * that RT, DL and IRQ signals have been updated before updating CFS.

> >>>>       */

> >>>>      curr_class = rq->curr->sched_class;

> >>>> -    update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> >>>> -    update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> >>>> -    update_irq_load_avg(rq, 0);

> >>>> +    decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> >>>> +    decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> >>>> +    decayed |= update_irq_load_avg(rq, 0);

> >>

> >> Why not 'decayed  = update_cfs_rq_load_avg()' like in the

> >> !CONFIG_FAIR_GROUP_SCHED case?

> > 

> > Because it is handled by the update_load_avg() in

> > for_each_leaf_cfs_rq_safe() loop

> > 

> > This means that we can have 2 calls to cpufreq_update_util in

> > update_blocked_average() but at least the values will be up to date in

> > both calls unlike previously.

> > 

> > I'm going to prepare an additional patch to remove this useless call.

> > I have also seen some possible further optimization that i need to

> > study a bit more before preparing a patch

> 

> I see. The update_load_avg() call for the taskgroup skeleton se

> (cfs_rq->tg->se[cpu]). But what happens to the cpu which only has the

> root cfs_rq i the list? It doesn't have a skeleton se.


you're right. I have to add the following to make sure it will be called

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2eb1aa8..9fc077c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7604,9 +7604,13 @@ static void update_blocked_averages(int cpu)
                        cpu,
                        cfs_rq == &rq->cfs ? 0 : (long)cfs_rq->tg );
 
-               if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq))
+               if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) {
                        update_tg_load_avg(cfs_rq, 0);
 
+                       if (cfs_rq == &rq->cfs)
+                               decayed = 1;
+               }
+
                trace_sched_load_contrib_blocked(cpu,
                        &cfs_rq->avg,
                        cfs_rq == &rq->cfs ? 0 : (long)cfs_rq->tg );
Vincent Guittot Nov. 13, 2019, 6:09 p.m. UTC | #4
Le Wednesday 13 Nov 2019 à 18:50:35 (+0100), Vincent Guittot a écrit :
> Le Wednesday 13 Nov 2019 à 15:09:47 (+0100), Dietmar Eggemann a écrit :

> > On 13.11.19 14:30, Vincent Guittot wrote:

> > > On Wed, 13 Nov 2019 at 11:50, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:

> > >>

> > >> On 12.11.19 16:05, Vincent Guittot wrote:

> > >>> Le Tuesday 12 Nov 2019 à 15:48:13 (+0100), Vincent Guittot a écrit :

> > 

> > [...]

> > 

> > >>>> @@ -7493,9 +7495,9 @@ static void update_blocked_averages(int cpu)

> > >>>>       * that RT, DL and IRQ signals have been updated before updating CFS.

> > >>>>       */

> > >>>>      curr_class = rq->curr->sched_class;

> > >>>> -    update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> > >>>> -    update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> > >>>> -    update_irq_load_avg(rq, 0);

> > >>>> +    decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);

> > >>>> +    decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);

> > >>>> +    decayed |= update_irq_load_avg(rq, 0);

> > >>

> > >> Why not 'decayed  = update_cfs_rq_load_avg()' like in the

> > >> !CONFIG_FAIR_GROUP_SCHED case?

> > > 

> > > Because it is handled by the update_load_avg() in

> > > for_each_leaf_cfs_rq_safe() loop

> > > 

> > > This means that we can have 2 calls to cpufreq_update_util in

> > > update_blocked_average() but at least the values will be up to date in

> > > both calls unlike previously.

> > > 

> > > I'm going to prepare an additional patch to remove this useless call.

> > > I have also seen some possible further optimization that i need to

> > > study a bit more before preparing a patch

> > 

> > I see. The update_load_avg() call for the taskgroup skeleton se

> > (cfs_rq->tg->se[cpu]). But what happens to the cpu which only has the

> > root cfs_rq i the list? It doesn't have a skeleton se.

> 

> you're right. I have to add the following to make sure it will be called

> 

> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c

> index 2eb1aa8..9fc077c 100644

> --- a/kernel/sched/fair.c

> +++ b/kernel/sched/fair.c

> @@ -7604,9 +7604,13 @@ static void update_blocked_averages(int cpu)

>                         cpu,

>                         cfs_rq == &rq->cfs ? 0 : (long)cfs_rq->tg );

>  

> -               if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq))

> +               if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) {

>                         update_tg_load_avg(cfs_rq, 0);

>  

> +                       if (cfs_rq == &rq->cfs)

> +                               decayed = 1;

> +               }

> +

>                 trace_sched_load_contrib_blocked(cpu,

>                         &cfs_rq->avg,

>                         cfs_rq == &rq->cfs ? 0 : (long)cfs_rq->tg );


the proper fix without some debug trace events :-)

@@ -7567,9 +7569,13 @@ static void update_blocked_averages(int cpu)
 	for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) {
 		struct sched_entity *se;
 
-		if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq))
+		if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) {
 			update_tg_load_avg(cfs_rq, 0);
 
+			if (cfs_rq == &rq->cfs)
+				decayed = 1;
+		}
+
 		/* Propagate pending load changes to the parent, if any: */
 		se = cfs_rq->tg->se[cpu];
 		if (se && !skip_blocked_update(se))



> 

>
diff mbox series

Patch

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e458f52..c93d534 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3508,9 +3508,6 @@  update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
 	cfs_rq->load_last_update_time_copy = sa->last_update_time;
 #endif
 
-	if (decayed)
-		cfs_rq_util_change(cfs_rq, 0);
-
 	return decayed;
 }
 
@@ -3620,8 +3617,12 @@  static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
 		attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION);
 		update_tg_load_avg(cfs_rq, 0);
 
-	} else if (decayed && (flags & UPDATE_TG))
-		update_tg_load_avg(cfs_rq, 0);
+	} else if (decayed) {
+		cfs_rq_util_change(cfs_rq, 0);
+
+		if (flags & UPDATE_TG)
+			update_tg_load_avg(cfs_rq, 0);
+	}
 }
 
 #ifndef CONFIG_64BIT
@@ -7484,6 +7485,7 @@  static void update_blocked_averages(int cpu)
 	const struct sched_class *curr_class;
 	struct rq_flags rf;
 	bool done = true;
+	int decayed = 0;
 
 	rq_lock_irqsave(rq, &rf);
 	update_rq_clock(rq);
@@ -7493,9 +7495,9 @@  static void update_blocked_averages(int cpu)
 	 * that RT, DL and IRQ signals have been updated before updating CFS.
 	 */
 	curr_class = rq->curr->sched_class;
-	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
-	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
-	update_irq_load_avg(rq, 0);
+	decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
+	decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
+	decayed |= update_irq_load_avg(rq, 0);
 
 	/* Don't need periodic decay once load/util_avg are null */
 	if (others_have_blocked(rq))
@@ -7529,6 +7531,9 @@  static void update_blocked_averages(int cpu)
 	}
 
 	update_blocked_load_status(rq, !done);
+
+	if (decayed)
+		cpufreq_update_util(rq, 0);
 	rq_unlock_irqrestore(rq, &rf);
 }
 
@@ -7585,6 +7590,7 @@  static inline void update_blocked_averages(int cpu)
 	struct cfs_rq *cfs_rq = &rq->cfs;
 	const struct sched_class *curr_class;
 	struct rq_flags rf;
+	int decayed = 0;
 
 	rq_lock_irqsave(rq, &rf);
 	update_rq_clock(rq);
@@ -7594,13 +7600,16 @@  static inline void update_blocked_averages(int cpu)
 	 * that RT, DL and IRQ signals have been updated before updating CFS.
 	 */
 	curr_class = rq->curr->sched_class;
-	update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
-	update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
-	update_irq_load_avg(rq, 0);
+	decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
+	decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
+	decayed |= update_irq_load_avg(rq, 0);
 
-	update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);
+	decayed |= update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);
 
 	update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq));
+
+	if (decayed)
+		cpufreq_update_util(rq, 0);
 	rq_unlock_irqrestore(rq, &rf);
 }