From: Hao Jia <jiahao.os@bytedance.com>
To: mingo@redhat.com, peterz@infradead.org, mingo@kernel.org,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
vschneid@redhat.com, mgorman@techsingularity.net
Cc: linux-kernel@vger.kernel.org, Hao Jia <jiahao.os@bytedance.com>
Subject: [PATCH 2/2] sched/core: Optimize the order of scanning CPU
Date: Fri, 21 Oct 2022 14:15:58 +0800 [thread overview]
Message-ID: <20221021061558.34767-3-jiahao.os@bytedance.com> (raw)
In-Reply-To: <20221021061558.34767-1-jiahao.os@bytedance.com>
When select_idle_capacity() starts scanning for an idle CPU, it starts
with target CPU that has already been checked in select_idle_sibling().
So, we finally try the target CPU. Similarly for task_numa_assign(),
we have just checked numa_migrate_on of dst_cpu, so start from the
next CPU. This also works for steal_cookie_task(), the first scan
must fail and start directly from the next one.
Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
---
kernel/sched/core.c | 2 +-
kernel/sched/fair.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5800b0623ff3..f6ad68714546 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6154,7 +6154,7 @@ static bool steal_cookie_task(int cpu, struct sched_domain *sd)
{
int i;
- for_each_cpu_wrap(i, sched_domain_span(sd), cpu) {
+ for_each_cpu_wrap(i, sched_domain_span(sd), cpu + 1) {
if (i == cpu)
continue;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b7cbec539c77..d95ee285734e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1824,7 +1824,7 @@ static void task_numa_assign(struct task_numa_env *env,
int start = env->dst_cpu;
/* Find alternative idle CPU. */
- for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start) {
+ for_each_cpu_wrap(cpu, cpumask_of_node(env->dst_nid), start + 1) {
if (cpu == env->best_cpu || !idle_cpu(cpu) ||
!cpumask_test_cpu(cpu, env->p->cpus_ptr)) {
continue;
@@ -6663,7 +6663,7 @@ select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
task_util = uclamp_task_util(p);
- for_each_cpu_wrap(cpu, cpus, target) {
+ for_each_cpu_wrap(cpu, cpus, target + 1) {
unsigned long cpu_cap = capacity_of(cpu);
if (!available_idle_cpu(cpu) && !sched_idle_cpu(cpu))
--
2.37.0
next prev parent reply other threads:[~2022-10-21 6:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-21 6:15 [PATCH 0/2] Optimize the process of scanning CPU for some functions Hao Jia
2022-10-21 6:15 ` [PATCH 1/2] sched/numa: Stop an exhastive search if an idle core is found Hao Jia
2022-10-24 13:34 ` Mel Gorman
2022-10-25 3:16 ` [External] " Hao Jia
2022-10-25 9:32 ` Mel Gorman
2022-10-25 11:10 ` Hao Jia
2022-10-25 13:32 ` Mel Gorman
2022-10-26 2:30 ` Hao Jia
2022-10-21 6:15 ` Hao Jia [this message]
2022-10-24 10:00 ` [PATCH 0/2] Optimize the process of scanning CPU for some functions Peter Zijlstra
2022-10-24 12:07 ` [External] " Hao Jia
2022-10-24 13:01 ` Hao Jia
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