This article can be found at: https://www.ebpf.top/post/bpf_sched_ext_dive_into Linux Process Scheduler CFS Scheduler EEVDF Scheduler Implementation Mechanism of BPF Scheduler Extender sched_ext Addition 1: SCHED_EXT Scheduling Class Addition 2: eBPF Custom Scheduler Functions Workflow of SCHED_EXT Scheduling Class Scheduling Cycle Workflow Switching to sched_ext Summary In the article Linus Strongly Pushes for Inclusion: BPF Empowers Scheduler Success, we reviewed the journey of BPF in the scheduler integration process within the community. Patch V7 is prepared for merging into 6.11, and subsequently, the code repository has also changed to kernel git address. It is only a matter of time for the merge to happen. This blog post will focus on the implementation principles of sched_ext. sched_ext is an extensible scheduler class jointly introduced by Meta and Google, referred to as ext_sched_class or sched_ext. This mechanism allows users to optimize scheduler strategies for specific workloads or scenarios by implementing scheduling classes through defined BPF programs.……

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Read more at: https://www.ebpf.top/post/bpf_sched_ext 1. The Emergence of Pluggable Scheduler [2004] In 2004, Con Kolivas from the Linux community proposed the idea of a pluggable scheduler, envisioning multiple schedulers in the kernel that users could choose during boot. The principle behind the patch submission involved splitting a significant amount of code into a common part in kernel/sched.c and a private part. It also included pointers in the scheduler.c file that directed functions handling scheduling tasks, which were invoked for various process events (fork(), exit(), etc.), to gather scheduling-related information. Implementing a new scheduler simply required writing replacement functions and integrating them. However, this submission faced strong opposition from community developer Ingo Molnar, who believed that having pluggable schedulers would discourage patches for scheduling domains and instead lead to separate schedulers for specific scenarios like NUMA scheduling and SMP scheduling. Ingo Molnar’s standpoint was clear: If everyone focuses on their own little family, the scheduler as a big family will lack organization and code contributions, leading to the existence of schedulers tailored to specific scenarios.……

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