On 2020/11/30 22:47, Vincent Guittot wrote: > On Mon, 30 Nov 2020 at 15:40, Mel Gorman <mgor...@techsingularity.net> wrote: >> >> 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. > > Good point
This is more reasonable, thanks Mel. > >> >> Signed-off-by: Mel Gorman <mgor...@techsingularity.net> > > Reviewed-by: Vincent Guittot <vincent.guit...@linaro.org> > >> --- >> 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 0d54d69ba1a5..d9acd55d309b 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -6087,10 +6087,11 @@ 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)); >> } >> >> /*
