[tip: sched/core] sched/fair: Clear SMT siblings after determining the core is not idle
The following commit has been merged into the sched/core branch of tip: Commit-ID: 13d5a5e9f9b8515da3c04305ae1bb03ab91be7a7 Gitweb: https://git.kernel.org/tip/13d5a5e9f9b8515da3c04305ae1bb03ab91be7a7 Author:Mel Gorman AuthorDate:Mon, 30 Nov 2020 14:40:20 Committer: Ingo Molnar CommitterDate: Fri, 11 Dec 2020 10:30:38 +01:00 sched/fair: Clear SMT siblings after determining the core is not idle The clearing of SMT siblings from the SIS mask before checking for an idle core is a small but unnecessary cost. Defer the clearing of the siblings until the scan moves to the next potential target. The cost of this was not measured as it is borderline noise but it should be self-evident. Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Vincent Guittot Link: https://lkml.kernel.org/r/20201130144020.gs3...@techsingularity.net --- kernel/sched/fair.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f5dceda..efac224 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6086,10 +6086,11 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int break; } } - cpumask_andnot(cpus, cpus, cpu_smt_mask(core)); if (idle) return core; + + cpumask_andnot(cpus, cpus, cpu_smt_mask(core)); } /*
[tip: sched/core] sched/fair: Clear SMT siblings after determining the core is not idle
The following commit has been merged into the sched/core branch of tip: Commit-ID: 82b738de57d571cd366d89e75b5fd60f3060852b Gitweb: https://git.kernel.org/tip/82b738de57d571cd366d89e75b5fd60f3060852b Author:Mel Gorman AuthorDate:Mon, 30 Nov 2020 14:40:20 Committer: Peter Zijlstra CommitterDate: Thu, 03 Dec 2020 10:00:36 +01:00 sched/fair: Clear SMT siblings after determining the core is not idle The clearing of SMT siblings from the SIS mask before checking for an idle core is a small but unnecessary cost. Defer the clearing of the siblings until the scan moves to the next potential target. The cost of this was not measured as it is borderline noise but it should be self-evident. Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Vincent Guittot Link: https://lkml.kernel.org/r/20201130144020.gs3...@techsingularity.net --- kernel/sched/fair.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f5dceda..efac224 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6086,10 +6086,11 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int break; } } - cpumask_andnot(cpus, cpus, cpu_smt_mask(core)); if (idle) return core; + + cpumask_andnot(cpus, cpus, cpu_smt_mask(core)); } /*
