diff options
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 53 | ||||
| -rw-r--r-- | init/init_task.c | 3 |
2 files changed, 55 insertions, 1 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 config GENERIC_SCHED_CLOCK bool +menu "Scheduler features" + +config UCLAMP_TASK + bool "Enable utilization clamping for RT/FAIR tasks" + depends on CPU_FREQ_GOV_SCHEDUTIL + 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. + +config UCLAMP_BUCKETS_COUNT + 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 + will be SCHED_CAPACITY_SCALE/UCLAMP_BUCKETS_COUNT. The higher the + 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. + +endmenu + # # For architectures that want to enable the support for NUMA-affine scheduler # balancing logic: diff --git a/init/init_task.c b/init/init_task.c index afa6ad795355..7ab773b9b3cd 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -72,7 +72,8 @@ struct task_struct init_task .static_prio = MAX_PRIO - 20, .normal_prio = MAX_PRIO - 20, .policy = SCHED_NORMAL, - .cpus_allowed = CPU_MASK_ALL, + .cpus_ptr = &init_task.cpus_mask, + .cpus_mask = CPU_MASK_ALL, .nr_cpus_allowed= NR_CPUS, .mm = NULL, .active_mm = &init_mm, |