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    SubjectRe: [PATCH v7 3/7] sched: add utilization_avg_contrib
    On 07/10/14 13:13, Vincent Guittot wrote:
    > Add new statistics which reflect the average time a task is running on the CPU
    > and the sum of these running time of the tasks on a runqueue. The latter is
    > named utilization_avg_contrib.
    >
    > This patch is based on the usage metric that was proposed in the 1st
    > versions of the per-entity load tracking patchset by Paul Turner
    > <pjt@google.com> but that has be removed afterward. This version differs
    > from the original one in the sense that it's not linked to task_group.
    >
    > The rq's utilization_avg_contrib will be used to check if a rq is overloaded
    > or not instead of trying to compute how many task a group of CPUs can handle
    >
    > Rename runnable_avg_period into avg_period as it is now used with both
    > runnable_avg_sum and running_avg_sum
    >
    > Add some descriptions of the variables to explain their differences
    >
    > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
    > ---
    > include/linux/sched.h | 21 +++++++++++++---
    > kernel/sched/debug.c | 9 ++++---
    > kernel/sched/fair.c | 70 +++++++++++++++++++++++++++++++++++++++------------
    > kernel/sched/sched.h | 8 +++++-
    > 4 files changed, 84 insertions(+), 24 deletions(-)
    >

    [...]

    > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
    > index 9075dee..d6de526 100644
    > --- a/kernel/sched/fair.c
    > +++ b/kernel/sched/fair.c
    > @@ -678,8 +678,8 @@ void init_task_runnable_average(struct task_struct *p)
    >
    > p->se.avg.decay_count = 0;
    > slice = sched_slice(task_cfs_rq(p), &p->se) >> 10;
    > - p->se.avg.runnable_avg_sum = slice;
    > - p->se.avg.runnable_avg_period = slice;
    > + p->se.avg.runnable_avg_sum = p->se.avg.running_avg_sum = slice;
    > + p->se.avg.avg_period = slice;
    > __update_task_entity_contrib(&p->se);

    Didn't you miss a call to __update_task_entity_utilization here?

    Another thing from the naming perspective: You use the term
    'utilization' for 'load' (e.g. existing __update_entity_load_avg_contrib
    versus new __update_entity_utilization_avg_contrib) but for the
    __update_task_entity_contrib function, you use the term 'utilization'
    for 'contrib'. IMHO, kind of hard to grasp.

    > }
    > #else
    > @@ -1548,7 +1548,7 @@ static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
    > *period = now - p->last_task_numa_placement;
    > } else {
    > delta = p->se.avg.runnable_avg_sum;
    > - *period = p->se.avg.runnable_avg_period;
    > + *period = p->se.avg.avg_period;
    > }
    >
    > p->last_sum_exec_runtime = runtime;




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