* [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix
@ 2022-04-15 2:22 Tao Zhou
2022-04-15 8:32 ` Vincent Guittot
0 siblings, 1 reply; 5+ messages in thread
From: Tao Zhou @ 2022-04-15 2:22 UTC (permalink / raw)
To: LKML, Tao Zhou
Cc: Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
Dietmar Eggemann, Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira
If busiest group type is group_misfit_task, the local
group type must be group_has_spare according to below
code in update_sd_pick_busiest():
if (sgs->group_type == group_misfit_task &&
(!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
sds->local_stat.group_type != group_has_spare))
return false;
group type imbalanced and overloaded and fully_busy are filtered in here.
misfit and asym are filtered before in update_sg_lb_stats().
So, change the decision matrix to:
busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
has_spare nr_idle balanced N/A N/A balanced balanced
fully_busy nr_idle nr_idle N/A N/A balanced balanced
misfit_task force N/A N/A N/A *N/A* *N/A*
asym_packing force force N/A N/A force force
imbalanced force force N/A N/A force force
overloaded force force N/A N/A force avg_load
Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()")
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Tao Zhou <tao.zhou@linux.dev>
---
v1 changelog:
(1) Send to MAINTAINERS/REVIEWS get from `./scripts/get_maintainer.pl`
suggested by Dietmar Eggemann.
(2) Based on v5.18-rc2
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d4bd299d67ab..b8c67e7c8cf3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9495,7 +9495,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
* has_spare nr_idle balanced N/A N/A balanced balanced
* fully_busy nr_idle nr_idle N/A N/A balanced balanced
- * misfit_task force N/A N/A N/A force force
+ * misfit_task force N/A N/A N/A N/A N/A
* asym_packing force force N/A N/A force force
* imbalanced force force N/A N/A force force
* overloaded force force N/A N/A force avg_load
--
2.35.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix
2022-04-15 2:22 [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix Tao Zhou
@ 2022-04-15 8:32 ` Vincent Guittot
2022-04-15 10:03 ` Tao Zhou
2022-04-15 11:33 ` Peter Zijlstra
0 siblings, 2 replies; 5+ messages in thread
From: Vincent Guittot @ 2022-04-15 8:32 UTC (permalink / raw)
To: Tao Zhou
Cc: LKML, Ingo Molnar, Peter Zijlstra, Juri Lelli, Dietmar Eggemann,
Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira
On Fri, 15 Apr 2022 at 04:22, Tao Zhou <tao.zhou@linux.dev> wrote:
>
> If busiest group type is group_misfit_task, the local
> group type must be group_has_spare according to below
> code in update_sd_pick_busiest():
>
> if (sgs->group_type == group_misfit_task &&
> (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
> sds->local_stat.group_type != group_has_spare))
> return false;
>
> group type imbalanced and overloaded and fully_busy are filtered in here.
> misfit and asym are filtered before in update_sg_lb_stats().
The behavior has changed with
cad68e552e77 ("sched/fair: Consider misfit tasks when load-balancing")
But we haven't updated the matrix
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
> So, change the decision matrix to:
>
> busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
> has_spare nr_idle balanced N/A N/A balanced balanced
> fully_busy nr_idle nr_idle N/A N/A balanced balanced
> misfit_task force N/A N/A N/A *N/A* *N/A*
> asym_packing force force N/A N/A force force
> imbalanced force force N/A N/A force force
> overloaded force force N/A N/A force avg_load
>
> Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()")
> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Signed-off-by: Tao Zhou <tao.zhou@linux.dev>
> ---
>
> v1 changelog:
> (1) Send to MAINTAINERS/REVIEWS get from `./scripts/get_maintainer.pl`
> suggested by Dietmar Eggemann.
> (2) Based on v5.18-rc2
>
>
> kernel/sched/fair.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index d4bd299d67ab..b8c67e7c8cf3 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9495,7 +9495,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
> * busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
> * has_spare nr_idle balanced N/A N/A balanced balanced
> * fully_busy nr_idle nr_idle N/A N/A balanced balanced
> - * misfit_task force N/A N/A N/A force force
> + * misfit_task force N/A N/A N/A N/A N/A
> * asym_packing force force N/A N/A force force
> * imbalanced force force N/A N/A force force
> * overloaded force force N/A N/A force avg_load
> --
> 2.35.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix
2022-04-15 8:32 ` Vincent Guittot
@ 2022-04-15 10:03 ` Tao Zhou
2022-04-15 11:33 ` Peter Zijlstra
1 sibling, 0 replies; 5+ messages in thread
From: Tao Zhou @ 2022-04-15 10:03 UTC (permalink / raw)
To: Vincent Guittot, Tao Zhou
Cc: LKML, Ingo Molnar, Peter Zijlstra, Juri Lelli, Dietmar Eggemann,
Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira
On Fri, Apr 15, 2022 at 10:32:09AM +0200,
Vincent Guittot wrote:
> On Fri, 15 Apr 2022 at 04:22, Tao Zhou <tao.zhou@linux.dev> wrote:
> >
> > If busiest group type is group_misfit_task, the local
> > group type must be group_has_spare according to below
> > code in update_sd_pick_busiest():
> >
> > if (sgs->group_type == group_misfit_task &&
> > (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
> > sds->local_stat.group_type != group_has_spare))
> > return false;
> >
> > group type imbalanced and overloaded and fully_busy are filtered in here.
> > misfit and asym are filtered before in update_sg_lb_stats().
>
> The behavior has changed with
> cad68e552e77 ("sched/fair: Consider misfit tasks when load-balancing")
> But we haven't updated the matrix
>
> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
I send a version just now but forget to change the version number.
Thanks,
Tao
> > So, change the decision matrix to:
> >
> > busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
> > has_spare nr_idle balanced N/A N/A balanced balanced
> > fully_busy nr_idle nr_idle N/A N/A balanced balanced
> > misfit_task force N/A N/A N/A *N/A* *N/A*
> > asym_packing force force N/A N/A force force
> > imbalanced force force N/A N/A force force
> > overloaded force force N/A N/A force avg_load
> >
> > Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()")
> > Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> > Signed-off-by: Tao Zhou <tao.zhou@linux.dev>
> > ---
> >
> > v1 changelog:
> > (1) Send to MAINTAINERS/REVIEWS get from `./scripts/get_maintainer.pl`
> > suggested by Dietmar Eggemann.
> > (2) Based on v5.18-rc2
> >
> >
> > kernel/sched/fair.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index d4bd299d67ab..b8c67e7c8cf3 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -9495,7 +9495,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
> > * busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
> > * has_spare nr_idle balanced N/A N/A balanced balanced
> > * fully_busy nr_idle nr_idle N/A N/A balanced balanced
> > - * misfit_task force N/A N/A N/A force force
> > + * misfit_task force N/A N/A N/A N/A N/A
> > * asym_packing force force N/A N/A force force
> > * imbalanced force force N/A N/A force force
> > * overloaded force force N/A N/A force avg_load
> > --
> > 2.35.2
> >
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix
2022-04-15 8:32 ` Vincent Guittot
2022-04-15 10:03 ` Tao Zhou
@ 2022-04-15 11:33 ` Peter Zijlstra
1 sibling, 0 replies; 5+ messages in thread
From: Peter Zijlstra @ 2022-04-15 11:33 UTC (permalink / raw)
To: Vincent Guittot
Cc: Tao Zhou, LKML, Ingo Molnar, Juri Lelli, Dietmar Eggemann,
Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira
On Fri, Apr 15, 2022 at 10:32:09AM +0200, Vincent Guittot wrote:
> On Fri, 15 Apr 2022 at 04:22, Tao Zhou <tao.zhou@linux.dev> wrote:
> >
> > If busiest group type is group_misfit_task, the local
> > group type must be group_has_spare according to below
> > code in update_sd_pick_busiest():
> >
> > if (sgs->group_type == group_misfit_task &&
> > (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
> > sds->local_stat.group_type != group_has_spare))
> > return false;
> >
> > group type imbalanced and overloaded and fully_busy are filtered in here.
> > misfit and asym are filtered before in update_sg_lb_stats().
>
> The behavior has changed with
> cad68e552e77 ("sched/fair: Consider misfit tasks when load-balancing")
> But we haven't updated the matrix
>
> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Thanks (I took the later version and stuck your Rb on)!
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix
@ 2022-04-15 9:55 Tao Zhou
0 siblings, 0 replies; 5+ messages in thread
From: Tao Zhou @ 2022-04-15 9:55 UTC (permalink / raw)
To: LKML, Tao Zhou
Cc: Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot,
Dietmar Eggemann, Steven Rostedt, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira, Morten Rasmussen, Valentin Schneider
If busiest group type is group_misfit_task, the local
group type must be group_has_spare according to below
code in update_sd_pick_busiest():
if (sgs->group_type == group_misfit_task &&
(!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
sds->local_stat.group_type != group_has_spare))
return false;
group type imbalanced and overloaded and fully_busy are filtered in here.
misfit and asym are filtered before in update_sg_lb_stats().
So, change the decision matrix to:
busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
has_spare nr_idle balanced N/A N/A balanced balanced
fully_busy nr_idle nr_idle N/A N/A balanced balanced
misfit_task force N/A N/A N/A *N/A* *N/A*
asym_packing force force N/A N/A force force
imbalanced force force N/A N/A force force
overloaded force force N/A N/A force avg_load
Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()")
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Tao Zhou <tao.zhou@linux.dev>
---
v1 changelog:
(1) Send to MAINTAINERS/REVIEWS get from `./scripts/get_maintainer.pl`
suggested by Dietmar Eggemann.
(2) Based on v5.18-rc2
v1->v2 changelog:
(1) Add Reviewed-by from Vincent Guittot.
(2) This behavior has changed with
cad68e552e77 ("sched/fair: Consider misfit tasks when load-balancing")
and the matrix has not changed.
Add the related people of commit cad68e552e77 to the cc list.
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d4bd299d67ab..b8c67e7c8cf3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9495,7 +9495,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
* has_spare nr_idle balanced N/A N/A balanced balanced
* fully_busy nr_idle nr_idle N/A N/A balanced balanced
- * misfit_task force N/A N/A N/A force force
+ * misfit_task force N/A N/A N/A N/A N/A
* asym_packing force force N/A N/A force force
* imbalanced force force N/A N/A force force
* overloaded force force N/A N/A force avg_load
--
2.35.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
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2022-04-15 2:22 [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix Tao Zhou
2022-04-15 8:32 ` Vincent Guittot
2022-04-15 10:03 ` Tao Zhou
2022-04-15 11:33 ` Peter Zijlstra
2022-04-15 9:55 Tao Zhou
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