From 754a1227925ca988797de9d56b16c7c1616418c6 Mon Sep 17 00:00:00 2001 From: Patrick Bellasi Date: Mon, 22 Jun 2015 18:11:44 +0100 Subject: sched/tune: add sysctl interface to define a boost value The current (CFS) scheduler implementation does not allow "to boost" tasks performance by running them at a higher OPP compared to the minimum required to meet their workload demands. To support tasks performance boosting the scheduler should provide a "knob" which allows to tune how much the system is going to be optimised for energy efficiency vs performance. This patch is the first of a series which provides a simple interface to define a tuning knob. One system-wide "boost" tunable is exposed via: /proc/sys/kernel/sched_cfs_boost which can be configured in the range [0..100], to define a percentage where: - 0% boost requires to operate in "standard" mode by scheduling tasks at the minimum capacities required by the workload demand - 100% boost requires to push at maximum the task performances, "regardless" of the incurred energy consumption A boost value in between these two boundaries is used to bias the power/performance trade-off, the higher the boost value the more the scheduler is biased toward performance boosting instead of energy efficiency. Change-Id: I59a41725e2d8f9238a61dfb0c909071b53560fc0 cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Patrick Bellasi Git-commit: 63c8fad2b06805ef88f1220551289f0a3c3529f1 Git-repo: https://source.codeaurora.org/quic/la/kernel/msm-4.4 Signed-off-by: Vikram Mulukutla --- init/Kconfig | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'init/Kconfig') diff --git a/init/Kconfig b/init/Kconfig index 6020a351c57b..311669332867 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1264,6 +1264,32 @@ config SCHED_AUTOGROUP desktop applications. Task group autogeneration is currently based upon task session. +config SCHED_TUNE + bool "Boosting for CFS tasks (EXPERIMENTAL)" + help + This option enables the system-wide support for task boosting. + When this support is enabled a new sysctl interface is exposed to + userspace via: + /proc/sys/kernel/sched_cfs_boost + which allows to set a system-wide boost value in range [0..100]. + + The currently boosting strategy is implemented in such a way that: + - a 0% boost value requires to operate in "standard" mode by + scheduling all tasks at the minimum capacities required by their + workload demand + - a 100% boost value requires to push at maximum the task + performances, "regardless" of the incurred energy consumption + + A boost value in between these two boundaries is used to bias the + power/performance trade-off, the higher the boost value the more the + scheduler is biased toward performance boosting instead of energy + efficiency. + + Since this support exposes a single system-wide knob, the specified + boost value is applied to all (CFS) tasks in the system. + + If unsure, say N. + config SYSFS_DEPRECATED bool "Enable deprecated sysfs features to support old userspace tools" depends on SYSFS -- cgit v1.2.3