lkml.org 
[lkml]   [2014]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 6/7] sched: Make sched entity usage tracking scale-invariant
Date
Apply scale-invariance correction factor to usage tracking as well.

cc: Paul Turner <pjt@google.com>
cc: Ben Segall <bsegall@google.com>

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
kernel/sched/fair.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d8a8c83..c7aa8c1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2302,9 +2302,9 @@ static __always_inline int __update_entity_runnable_avg(u64 now, int cpu,
int runnable,
int running)
{
- u64 delta, periods;
- u32 runnable_contrib;
- int delta_w, decayed = 0;
+ u64 delta, scaled_delta, periods;
+ u32 runnable_contrib, scaled_runnable_contrib;
+ int delta_w, scaled_delta_w, decayed = 0;
u32 scale_cap = arch_scale_load_capacity(cpu);

delta = now - sa->last_runnable_update;
@@ -2339,11 +2339,12 @@ static __always_inline int __update_entity_runnable_avg(u64 now, int cpu,
*/
delta_w = 1024 - delta_w;

+ scaled_delta_w = (delta_w * scale_cap) >> SCHED_CAPACITY_SHIFT;
+
if (runnable)
- sa->runnable_avg_sum += (delta_w * scale_cap)
- >> SCHED_CAPACITY_SHIFT;
+ sa->runnable_avg_sum += scaled_delta_w;
if (running)
- sa->usage_avg_sum += delta_w;
+ sa->usage_avg_sum += scaled_delta_w;
sa->runnable_avg_period += delta_w;

delta -= delta_w;
@@ -2361,20 +2362,23 @@ static __always_inline int __update_entity_runnable_avg(u64 now, int cpu,
/* Efficiently calculate \sum (1..n_period) 1024*y^i */
runnable_contrib = __compute_runnable_contrib(periods);

- if (runnable)
- sa->runnable_avg_sum += (runnable_contrib * scale_cap)
+ scaled_runnable_contrib = (runnable_contrib * scale_cap)
>> SCHED_CAPACITY_SHIFT;
+
+ if (runnable)
+ sa->runnable_avg_sum += scaled_runnable_contrib;
if (running)
- sa->usage_avg_sum += runnable_contrib;
+ sa->usage_avg_sum += scaled_runnable_contrib;
sa->runnable_avg_period += runnable_contrib;
}

/* Remainder of delta accrued against u_0` */
+ scaled_delta = (delta * scale_cap) >> SCHED_CAPACITY_SHIFT;
+
if (runnable)
- sa->runnable_avg_sum += (delta * scale_cap)
- >> SCHED_CAPACITY_SHIFT;
+ sa->runnable_avg_sum += scaled_delta;
if (running)
- sa->usage_avg_sum += delta;
+ sa->usage_avg_sum += scaled_delta;
sa->runnable_avg_period += delta;

return decayed;
--
1.7.9.5



\
 
 \ /
  Last update: 2014-09-22 19:01    [W:0.285 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site