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/init/Kconfig b/init/Kconfig
index b0bfdde..d7dd52f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -400,6 +400,15 @@
If in doubt, say N here.
+config SCHED_WALT
+ bool "Support window based load tracking"
+ depends on SMP
+ help
+ This feature will allow the scheduler to maintain a tunable window
+ based set of metrics for tasks and runqueues. These metrics can be
+ used to guide task placement as well as task frequency requirements
+ for cpufreq governors.
+
config BSD_PROCESS_ACCT
bool "BSD Process Accounting"
depends on MULTIUSER