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authorSrivatsa Vaddagiri <vatsa@codeaurora.org>2016-05-31 09:08:38 -0700
committerJohn Stultz <john.stultz@linaro.org>2016-08-11 14:26:43 -0700
commitefb86bd08a2e9217d0b3c33753cf63d27e7c86da (patch)
treecdb222d246119fbc83dedb67fd29bd9f6e0f410d /kernel/sched/rt.c
parent345be81dba1ba6c7ac1df2b9ba355fc290d5a73b (diff)
sched: Introduce Window Assisted Load Tracking (WALT)
use a window based view of time in order to track task demand and CPU utilization in the scheduler. Window Assisted Load Tracking (WALT) implementation credits: Srivatsa Vaddagiri, Steve Muckle, Syed Rameez Mustafa, Joonwoo Park, Pavan Kumar Kondeti, Olav Haugan 2016-03-06: Integration with EAS/refactoring by Vikram Mulukutla and Todd Kjos Change-Id: I21408236836625d4e7d7de1843d20ed5ff36c708 Includes fixes for issues: eas/walt: Use walt_ktime_clock() instead of ktime_get_ns() to avoid a race resulting in watchdog resets BUG: 29353986 Change-Id: Ic1820e22a136f7c7ebd6f42e15f14d470f6bbbdb Handle walt accounting anomoly during resume During resume, there is a corner case where on wakeup, a task's prev_runnable_sum can go negative. This is a workaround that fixes the condition and warns (instead of crashing). BUG: 29464099 Change-Id: I173e7874324b31a3584435530281708145773508 Signed-off-by: Todd Kjos <tkjos@google.com> Signed-off-by: Srinath Sridharan <srinathsr@google.com> Signed-off-by: Juri Lelli <juri.lelli@arm.com> [jstultz: fwdported to 4.4] Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel/sched/rt.c')
-rw-r--r--kernel/sched/rt.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 9694204660b7..be700bfa1ae4 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -8,6 +8,8 @@
#include <linux/slab.h>
#include <linux/irq_work.h>
+#include "walt.h"
+
int sched_rr_timeslice = RR_TIMESLICE;
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
@@ -1261,6 +1263,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
rt_se->timeout = 0;
enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
+ walt_inc_cumulative_runnable_avg(rq, p);
if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
@@ -1272,6 +1275,7 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
update_curr_rt(rq);
dequeue_rt_entity(rt_se);
+ walt_dec_cumulative_runnable_avg(rq, p);
dequeue_pushable_task(rq, p);
}