ANDROID: 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>
Signed-off-by: Andres Oportus <andresoportus@google.com>
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
index 604297a..836a389 100644
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -1,4 +1,5 @@
#include "sched.h"
+#include "walt.h"
/*
* stop-task scheduling class.
@@ -42,12 +43,14 @@
enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
add_nr_running(rq, 1);
+ walt_inc_cumulative_runnable_avg(rq, p);
}
static void
dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
sub_nr_running(rq, 1);
+ walt_dec_cumulative_runnable_avg(rq, p);
}
static void yield_task_stop(struct rq *rq)