CONFIG_SCHED_SCALABLE

Red/black tree ready queue

Type: bool

Help

When selected, the scheduler ready queue will be implemented as a red/black tree. This has rather slower constant-time insertion and removal overhead, and on most platforms (that are not otherwise using the rbtree somewhere) requires an extra ~2kb of code. But the resulting behavior will scale cleanly and quickly into the many thousands of threads. Use this on platforms where you may have many threads (very roughly: more than 20 or so) marked as runnable at a given time. Most applications don’t want this.

Direct dependencies

<choice SCHED_ALGORITHM: Scheduler priority queue algorithm>

(Includes any dependencies from ifs and menus.)

Kconfig definition

At kernel/Kconfig:228

Included via Kconfig:8Kconfig.zephyr:33

Menu path: (Top) → General Kernel Options → Scheduler priority queue algorithm

config SCHED_SCALABLE
    bool "Red/black tree ready queue"
    depends on <choice SCHED_ALGORITHM: Scheduler priority queue algorithm>
    help
      When selected, the scheduler ready queue will be implemented
      as a red/black tree.  This has rather slower constant-time
      insertion and removal overhead, and on most platforms (that
      are not otherwise using the rbtree somewhere) requires an
      extra ~2kb of code.  But the resulting behavior will scale
      cleanly and quickly into the many thousands of threads.  Use
      this on platforms where you may have many threads (very
      roughly: more than 20 or so) marked as runnable at a given
      time.  Most applications don't want this.

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