[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 12 Dec 2019 16:24:06 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Cheng Jian <cj.chengjian@...wei.com>
Cc: mingo@...nel.org, linux-kernel@...r.kernel.org,
chenwandun@...wei.com, xiexiuqi@...wei.com, liwei391@...wei.com,
huawei.libin@...wei.com, bobo.shaobowang@...wei.com,
juri.lelli@...hat.com, vincent.guittot@...aro.org
Subject: Re: [PATCH] sched/fair: Optimize select_idle_cpu
On Thu, Dec 12, 2019 at 10:41:02PM +0800, Cheng Jian wrote:
> Fixes: 1ad3aaf3fcd2 ("sched/core: Implement new approach to scale select_idle_cpu()")
The 'funny' thing is that select_idle_core() actually does the right
thing.
Copying that should work:
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 08a233e97a01..416d574dcebf 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5828,6 +5837,7 @@ static inline int select_idle_smt(struct task_struct *p, int target)
*/
static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int target)
{
+ struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
struct sched_domain *this_sd;
u64 avg_cost, avg_idle;
u64 time, cost;
@@ -5859,11 +5869,11 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t
time = cpu_clock(this);
- for_each_cpu_wrap(cpu, sched_domain_span(sd), target) {
+ cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr);
+
+ for_each_cpu_wrap(cpu, cpus, target) {
if (!--nr)
return si_cpu;
- if (!cpumask_test_cpu(cpu, p->cpus_ptr))
- continue;
if (available_idle_cpu(cpu))
break;
if (si_cpu == -1 && sched_idle_cpu(cpu))
Powered by blists - more mailing lists