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    Subject[RFCv4 PATCH 10/34] sched: Include blocked utilization in usage tracking
    Date
    Add the blocked utilization contribution to group sched_entity
    utilization (se->avg.utilization_avg_contrib) and to get_cpu_usage().
    With this change cpu usage now includes recent usage by currently
    non-runnable tasks, hence it provides a more stable view of the cpu
    usage. It does, however, also mean that the meaning of usage is changed:
    A cpu may be momentarily idle while usage is >0. It can no longer be
    assumed that cpu usage >0 implies runnable tasks on the rq.
    cfs_rq->utilization_load_avg or nr_running should be used instead to get
    the current rq status.

    cc: Ingo Molnar <mingo@redhat.com>
    cc: Peter Zijlstra <peterz@infradead.org>

    Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
    ---
    kernel/sched/fair.c | 11 ++++++++---
    1 file changed, 8 insertions(+), 3 deletions(-)

    diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
    index ad07398..e40cd88 100644
    --- a/kernel/sched/fair.c
    +++ b/kernel/sched/fair.c
    @@ -2789,7 +2789,8 @@ static long __update_entity_utilization_avg_contrib(struct sched_entity *se)
    __update_task_entity_utilization(se);
    else
    se->avg.utilization_avg_contrib =
    - group_cfs_rq(se)->utilization_load_avg;
    + group_cfs_rq(se)->utilization_load_avg +
    + group_cfs_rq(se)->utilization_blocked_avg;

    return se->avg.utilization_avg_contrib - old_contrib;
    }
    @@ -5046,13 +5047,17 @@ static int select_idle_sibling(struct task_struct *p, int target)

    static int get_cpu_usage(int cpu)
    {
    + int sum;
    unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg;
    + unsigned long blocked = cpu_rq(cpu)->cfs.utilization_blocked_avg;
    unsigned long capacity_orig = capacity_orig_of(cpu);

    - if (usage >= capacity_orig)
    + sum = usage + blocked;
    +
    + if (sum >= capacity_orig)
    return capacity_orig;

    - return usage;
    + return sum;
    }

    /*
    --
    1.9.1


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