CONFIG_NUM_PREEMPT_PRIORITIES

Number of preemptible priorities

Type: int

Help

Number of preemptible priorities available in the system. Gives access
to priorities 0 to CONFIG_NUM_PREEMPT_PRIORITIES - 1.

This can be set to 0 to disable preemptible scheduling.

The total number of priorities is

 NUM_COOP_PRIORITIES + NUM_PREEMPT_PRIORITIES + 1

The extra one is for the idle thread, which must run at the lowest
priority, and be the only thread at that priority.

Defaults

• 0 if !MULTITHREADING

• 15

Kconfig definition

At <Zephyr Kernel>/Kconfig:51

Included via Kconfig:8 → Kconfig.zephyr:40

Menu path: (Top) → General Kernel Options → Multi-threading

config NUM_PREEMPT_PRIORITIES
    int "Number of preemptible priorities" if MULTITHREADING
    range 0 128
    default 0 if !MULTITHREADING
    default 15
    help
      Number of preemptible priorities available in the system. Gives access
      to priorities 0 to CONFIG_NUM_PREEMPT_PRIORITIES - 1.

      This can be set to 0 to disable preemptible scheduling.

      The total number of priorities is

       NUM_COOP_PRIORITIES + NUM_PREEMPT_PRIORITIES + 1

      The extra one is for the idle thread, which must run at the lowest
      priority, and be the only thread at that priority.

(The ‘depends on’ condition includes propagated dependencies from ifs and menus.)