lkml.org 
[lkml]   [2022]   [Apr]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH] sched/fair: Return the busiest group only if imbalance is meaningful
    On Wed, 6 Apr 2022 at 13:23, zgpeng <zgpeng.linux@gmail.com> wrote:
    >
    > When calculate_imbalance function calculate the imbalance, it may
    > actually get a negative number. In this case, it is meaningless to

    We should not return a negative imbalance but I suppose this can
    happen when we are using the avg_load metrics to calculate imbalance.
    Have you faced a use case where imbalance is negative ?

    > return the so-called busiest group and continue to search for the
    > busiest cpu later. Therefore, only when the imbalance is greater
    > than 0 should return the busiest group, otherwise return NULL.
    >
    > Signed-off-by: zgpeng <zgpeng@tencent.com>
    > Reviewed-by: Samuel Liao <samuelliao@tencent.com>
    > ---
    > kernel/sched/fair.c | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
    > index 601f8bd..9f75303 100644
    > --- a/kernel/sched/fair.c
    > +++ b/kernel/sched/fair.c
    > @@ -9639,7 +9639,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
    > force_balance:
    > /* Looks like there is an imbalance. Compute it */
    > calculate_imbalance(env, &sds);
    > - return env->imbalance ? sds.busiest : NULL;
    > + return env->imbalance > 0 ? sds.busiest : NULL;
    >
    > out_balanced:
    > env->imbalance = 0;
    > --
    > 2.9.5
    >

    \
     
     \ /
      Last update: 2022-04-06 17:42    [W:5.309 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site