2020-05-20 13:45:02

by Dietmar Eggemann

Subject: [PATCH v3 1/5] sched/deadline: Optimize dl_bw_cpus()

Return the weight of the root domain (rd) span in case it is a subset
of the cpu_active_mask.

Continue to compute the number of CPUs over rd span and cpu_active_mask
when in hotplug.

Signed-off-by: Dietmar Eggemann <[email protected]>
---
kernel/sched/deadline.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 504d2f51b0d6..4ae22bfc37ae 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -54,10 +54,16 @@ static inline struct dl_bw *dl_bw_of(int i)
static inline int dl_bw_cpus(int i)
{
struct root_domain *rd = cpu_rq(i)->rd;
- int cpus = 0;
+ int cpus;

RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
"sched RCU must be held");
+
+ if (cpumask_subset(rd->span, cpu_active_mask))
+ return cpumask_weight(rd->span);
+
+ cpus = 0;
+
for_each_cpu_and(i, rd->span, cpu_active_mask)
cpus++;

--
2.17.1

2020-05-22 15:01:50

by Juri Lelli

Subject: Re: [PATCH v3 1/5] sched/deadline: Optimize dl_bw_cpus()

On 20/05/20 15:42, Dietmar Eggemann wrote:
> Return the weight of the root domain (rd) span in case it is a subset
> of the cpu_active_mask.
>
> Continue to compute the number of CPUs over rd span and cpu_active_mask
> when in hotplug.
>
> Signed-off-by: Dietmar Eggemann <[email protected]>
> ---
> kernel/sched/deadline.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 504d2f51b0d6..4ae22bfc37ae 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -54,10 +54,16 @@ static inline struct dl_bw *dl_bw_of(int i)
> static inline int dl_bw_cpus(int i)
> {
> struct root_domain *rd = cpu_rq(i)->rd;
> - int cpus = 0;
> + int cpus;
>
> RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
> "sched RCU must be held");
> +
> + if (cpumask_subset(rd->span, cpu_active_mask))
> + return cpumask_weight(rd->span);
> +
> + cpus = 0;
> +
> for_each_cpu_and(i, rd->span, cpu_active_mask)
> cpus++;
>
> --

Acked-by: Juri Lelli <[email protected]>

2020-06-16 12:27:00

by tip-bot2 for Alexey Makhalov

Subject: [tip: sched/core] sched/deadline: Optimize dl_bw_cpus()

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

Commit-ID: c81b89329933c6c0be809d4c0d2cb57c49153ee3
Gitweb: https://git.kernel.org/tip/c81b89329933c6c0be809d4c0d2cb57c49153ee3
Author: Dietmar Eggemann <[email protected]>
AuthorDate: Wed, 20 May 2020 15:42:39 +02:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Mon, 15 Jun 2020 14:10:04 +02:00

sched/deadline: Optimize dl_bw_cpus()

Return the weight of the root domain (rd) span in case it is a subset
of the cpu_active_mask.

Continue to compute the number of CPUs over rd span and cpu_active_mask
when in hotplug.

Signed-off-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Juri Lelli <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/sched/deadline.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index f31964a..ec90265 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -54,10 +54,16 @@ static inline struct dl_bw *dl_bw_of(int i)
static inline int dl_bw_cpus(int i)
{
struct root_domain *rd = cpu_rq(i)->rd;
- int cpus = 0;
+ int cpus;

RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
"sched RCU must be held");
+
+ if (cpumask_subset(rd->span, cpu_active_mask))
+ return cpumask_weight(rd->span);
+
+ cpus = 0;
+
for_each_cpu_and(i, rd->span, cpu_active_mask)
cpus++;