Messages in this thread | | | Subject | Re: [RFC PATCH 7/9] sched: search SMT before LLC domain | From | Subhra Mazumdar <> | Date | Thu, 5 Sep 2019 13:40:47 -0700 |
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On 9/5/19 2:31 AM, Peter Zijlstra wrote: > On Fri, Aug 30, 2019 at 10:49:42AM -0700, subhra mazumdar wrote: >> Search SMT siblings before all CPUs in LLC domain for idle CPU. This helps >> in L1 cache locality. >> --- >> kernel/sched/fair.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 8856503..94dd4a32 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -6274,11 +6274,11 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) >> return i; >> } >> >> - i = select_idle_cpu(p, sd, target); >> + i = select_idle_smt(p, target); >> if ((unsigned)i < nr_cpumask_bits) >> return i; >> >> - i = select_idle_smt(p, target); >> + i = select_idle_cpu(p, sd, target); >> if ((unsigned)i < nr_cpumask_bits) >> return i; >> > But it is absolutely conceptually wrong. An idle core is a much better > target than an idle sibling. This is select_idle_smt not select_idle_core.
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