path: root/init
diff options
Diffstat (limited to 'init')
1 files changed, 53 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 0e2344389501..c88289c18d59 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -677,6 +677,59 @@ config HAVE_UNSTABLE_SCHED_CLOCK
+menu "Scheduler features"
+ bool "Enable utilization clamping for RT/FAIR tasks"
+ help
+ This feature enables the scheduler to track the clamped utilization
+ of each CPU based on RUNNABLE tasks scheduled on that CPU.
+ With this option, the user can specify the min and max CPU
+ utilization allowed for RUNNABLE tasks. The max utilization defines
+ the maximum frequency a task should use while the min utilization
+ defines the minimum frequency it should use.
+ Both min and max utilization clamp values are hints to the scheduler,
+ aiming at improving its frequency selection policy, but they do not
+ enforce or grant any specific bandwidth for tasks.
+ If in doubt, say N.
+ int "Number of supported utilization clamp buckets"
+ range 5 20
+ default 5
+ depends on UCLAMP_TASK
+ help
+ Defines the number of clamp buckets to use. The range of each bucket
+ number of clamp buckets the finer their granularity and the higher
+ the precision of clamping aggregation and tracking at run-time.
+ For example, with the minimum configuration value we will have 5
+ clamp buckets tracking 20% utilization each. A 25% boosted tasks will
+ be refcounted in the [20..39]% bucket and will set the bucket clamp
+ effective value to 25%.
+ If a second 30% boosted task should be co-scheduled on the same CPU,
+ that task will be refcounted in the same bucket of the first task and
+ it will boost the bucket clamp effective value to 30%.
+ The clamp effective value of a bucket is reset to its nominal value
+ (20% in the example above) when there are no more tasks refcounted in
+ that bucket.
+ An additional boost/capping margin can be added to some tasks. In the
+ example above the 25% task will be boosted to 30% until it exits the
+ CPU. If that should be considered not acceptable on certain systems,
+ it's always possible to reduce the margin by increasing the number of
+ clamp buckets to trade off used memory for run-time tracking
+ precision.
+ If in doubt, use the default value.
# For architectures that want to enable the support for NUMA-affine scheduler
# balancing logic:

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