Thread (28 messages) 28 messages, 4 authors, 2014-11-24

[PATCH v7 3/7] sched: add utilization_avg_contrib

From: dietmar.eggemann@arm.com (Dietmar Eggemann)
Date: 2014-10-08 17:04:12
Also in: lkml

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
[off-list ref] 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(-)
[...]
quoted hunk ↗ jump to hunk
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.
quoted hunk ↗ jump to hunk
 }
 #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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