Re: [PATCH 06/16] sched: Disable WAKE_AFFINE for asymmetric configurations

Vincent Guittot
2016-05-24T09:10:53Z

On 23 May 2016 at 12:58, Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> If the system has cpu of different compute capacities (e.g. big.LITTLE)
> let affine wakeups be constrained to cpus of the same type.

Can you explain why you don't want wake affine with cpus with
different compute capacity ?

>
> cc: Ingo Molnar <mingo@redhat.com>
> cc: Peter Zijlstra <peterz@infradead.org>
>
> Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
> ---
> kernel/sched/core.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index d9619a3..558ec4a 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -6410,6 +6410,9 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
> sd->idle_idx = 1;
> }
>
> + if (sd->flags & SD_ASYM_CPUCAPACITY)
> + sd->flags &= ~SD_WAKE_AFFINE;
> +
> sd->private = &tl->data;
>
> return sd;
> --
> 1.9.1
>