This article explains the Linux kernel's CPU load‑balancing mechanism, covering concepts such as CPU load, balancing strategies, scheduling domains, groups, the PELT algorithm, CFS scheduling, trigger points, and practical code examples for both regular and real‑time tasks.
The article explains how Linux kernel scheduling uses a hierarchical topology—balancing load and preserving cache affinity—by mapping real‑world multi‑core hardware structures such as sockets, dies, clusters, and NUMA nodes to sched_domain and sched_group, and shows how to inspect and tune this layout with CONFIG_SCHED_DEBUG and QEMU simulation.
The article explains how Linux builds sched_domain and sched_group hierarchies based on physical CPU topology—sockets, dies, clusters, and NUMA nodes—illustrating load‑balancing (BALANCE) versus affinity (AFFINE) with concrete examples, kernel code references, and QEMU‑based experiments.
This article explains the concept of CPU load balancing, the hierarchical scheduler domain and group structures in a multi‑core SoC, when and how the Linux kernel performs periodic, no‑hz, and idle load‑balancing, and outlines the step‑by‑step algorithm used to migrate tasks for balanced system performance.
The article explains how the Linux CFS scheduler places newly created or awakened tasks—during fork, exec, or wake‑up—by using sched domains and flags to invoke select_task_rq_fair, which then chooses among energy‑aware, least‑loaded, or idle‑sibling CPUs based on capacity, energy impact, and affinity.
