lkml.org 
[lkml]   [2022]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: sched/urgent] sched/pelt: Relax the sync of load_sum with load_avg
The following commit has been merged into the sched/urgent branch of tip:

Commit-ID: 2d02fa8cc21a93da35cfba462bf8ab87bf2db651
Gitweb: https://git.kernel.org/tip/2d02fa8cc21a93da35cfba462bf8ab87bf2db651
Author: Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Tue, 11 Jan 2022 14:46:59 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 18 Jan 2022 12:09:58 +01:00

sched/pelt: Relax the sync of load_sum with load_avg

Similarly to util_avg and util_sum, don't sync load_sum with the low
bound of load_avg but only ensure that load_sum stays in the correct range.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Link: https://lkml.kernel.org/r/20220111134659.24961-5-vincent.guittot@linaro.org
---
kernel/sched/fair.c | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0e87e19..f4f02c2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3028,9 +3028,11 @@ enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
static inline void
dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- u32 divider = get_pelt_divider(&se->avg);
sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg);
- cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
+ sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum);
+ /* See update_cfs_rq_load_avg() */
+ cfs_rq->avg.load_sum = max_t(u32, cfs_rq->avg.load_sum,
+ cfs_rq->avg.load_avg * PELT_MIN_DIVIDER);
}
#else
static inline void
@@ -3513,9 +3515,10 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf
static inline void
update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq)
{
- long delta, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
+ long delta_avg, running_sum, runnable_sum = gcfs_rq->prop_runnable_sum;
unsigned long load_avg;
u64 load_sum = 0;
+ s64 delta_sum;
u32 divider;

if (!runnable_sum)
@@ -3542,7 +3545,7 @@ update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq
* assuming all tasks are equally runnable.
*/
if (scale_load_down(gcfs_rq->load.weight)) {
- load_sum = div_s64(gcfs_rq->avg.load_sum,
+ load_sum = div_u64(gcfs_rq->avg.load_sum,
scale_load_down(gcfs_rq->load.weight));
}

@@ -3559,19 +3562,22 @@ update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq
running_sum = se->avg.util_sum >> SCHED_CAPACITY_SHIFT;
runnable_sum = max(runnable_sum, running_sum);

- load_sum = (s64)se_weight(se) * runnable_sum;
- load_avg = div_s64(load_sum, divider);
-
- se->avg.load_sum = runnable_sum;
+ load_sum = se_weight(se) * runnable_sum;
+ load_avg = div_u64(load_sum, divider);

- delta = load_avg - se->avg.load_avg;
- if (!delta)
+ delta_avg = load_avg - se->avg.load_avg;
+ if (!delta_avg)
return;

- se->avg.load_avg = load_avg;
+ delta_sum = load_sum - (s64)se_weight(se) * se->avg.load_sum;

- add_positive(&cfs_rq->avg.load_avg, delta);
- cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * divider;
+ se->avg.load_sum = runnable_sum;
+ se->avg.load_avg = load_avg;
+ add_positive(&cfs_rq->avg.load_avg, delta_avg);
+ add_positive(&cfs_rq->avg.load_sum, delta_sum);
+ /* See update_cfs_rq_load_avg() */
+ cfs_rq->avg.load_sum = max_t(u32, cfs_rq->avg.load_sum,
+ cfs_rq->avg.load_avg * PELT_MIN_DIVIDER);
}

static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
@@ -3687,7 +3693,9 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)

r = removed_load;
sub_positive(&sa->load_avg, r);
- sa->load_sum = sa->load_avg * divider;
+ sub_positive(&sa->load_sum, r * divider);
+ /* See sa->util_sum below */
+ sa->load_sum = max_t(u32, sa->load_sum, sa->load_avg * PELT_MIN_DIVIDER);

r = removed_util;
sub_positive(&sa->util_avg, r);
\
 
 \ /
  Last update: 2022-01-18 12:19    [W:0.117 / U:1.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site