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SubjectRe: [RFCv3 PATCH 01/48] sched: add utilization_avg_contrib
On 11 February 2015 at 09:50, Preeti U Murthy <preeti@linux.vnet.ibm.com> wrote:
> On 02/05/2015 12:00 AM, Morten Rasmussen wrote:
>> From: Vincent Guittot <vincent.guittot@linaro.org>
>>
>> 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_load_avg.
>>
>> 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 afterwards. This version differs from
>> the original one in the sense that it's not linked to task_group.
>>
>> The rq's utilization_load_avg will be used to check if a rq is overloaded or
>> not instead of trying to compute how many tasks 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
>>
>> cc: Paul Turner <pjt@google.com>
>> cc: Ben Segall <bsegall@google.com>
>>
>> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
>> Acked-by: Morten Rasmussen <morten.rasmussen@arm.com>
>> ---
>> include/linux/sched.h | 21 ++++++++++++---
>> kernel/sched/debug.c | 10 ++++---
>> kernel/sched/fair.c | 74 ++++++++++++++++++++++++++++++++++++++++-----------
>> kernel/sched/sched.h | 8 +++++-
>> 4 files changed, 89 insertions(+), 24 deletions(-)
>
>> +static inline void __update_task_entity_utilization(struct sched_entity *se)
>> +{
>> + u32 contrib;
>> +
>> + /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */
>> + contrib = se->avg.running_avg_sum * scale_load_down(SCHED_LOAD_SCALE);
>> + contrib /= (se->avg.avg_period + 1);
>> + se->avg.utilization_avg_contrib = scale_load(contrib);
>> +}
>> +
>> +static long __update_entity_utilization_avg_contrib(struct sched_entity *se)
>> +{
>> + long old_contrib = se->avg.utilization_avg_contrib;
>> +
>> + if (entity_is_task(se))
>> + __update_task_entity_utilization(se);
>> +
>> + return se->avg.utilization_avg_contrib - old_contrib;
>
> When the entity is not a task, shouldn't the utilization_avg_contrib be
> updated like this :
>
> se->avg.utilization_avg_contrib = group_cfs_rq(se)->utilization_load_avg
> ? and then the delta with old_contrib be passed ?
>
> Or is this being updated someplace that I have missed ?

Patch 02 handles the contribution of entities which are not tasks.

Regards,
Vincent

>
> Regards
> Preeti U Murthy
>


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