CFS

Scheduling Mechanism of the Linux Kernel

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Scheduling Mechanism of the Linux Kernel

The Linux kernel’s scheduling mechanism supports various scheduling policies, categorized by priority from high to low: Deadline Scheduling (SCHED_DEADLINE): the highest priority, based on deadline scheduling, suitable for tasks with strict timing requirements. Real-time Scheduling includes SCHED_FIFO and SCHED_RR. SCHED_FIFO: first-in, first-out, with no time slice limit, until voluntarily relinquished or preempted by a higher-priority … Read more

New Optimization in Linux Scheduler: Merging cfs_rq and sched_entity for Dramatic Cache Hit Rate Improvement

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New Optimization in Linux Scheduler: Merging cfs_rq and sched_entity for Dramatic Cache Hit Rate Improvement

Abstract On the Linux 6.15 test kernel, a series of patches submitted by Google engineer Zecheng Li significantly reduces pointer jumps and cache misses by merging the <span><span>cfs_rq</span></span> (Completely Fair Scheduler run queue) with the <span><span>sched_entity</span></span> (scheduling entity) structure and switching to a per-CPU allocator. In large-scale cgroup hierarchical scenarios, this patch reduces LLC (Last … Read more

Linux Process Scheduling and Kernel Implementation

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Linux Process Scheduling and Kernel Implementation

This article mainly introduces Linux process scheduling and kernel implementation, in the following order: key data structures of process scheduling -> different scheduling methods -> scheduling triggers and process switching.1. Key Data Structures of Process Management1.1 task_struct task_struct is the structure used by the kernel to describe a process, including scheduling policy, priority, and other … Read more

Understanding the EEVDF Scheduler in Linux Kernel

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Understanding the EEVDF Scheduler in Linux Kernel

Linux 6.6 uses the EEVDF (Earliest Eligible Virtual Deadline First) scheduler to replace the CFS (Completely Fair Scheduler). Linux 6.12 completes the EEVDF scheduler by improving the handling of sleep process latency and supporting process time slice settings. The EEVDF scheduler considers schedule latency as one of the factors in process scheduling, ensuring fair allocation … Read more

Interesting Hack-A-Sat Satellite Hacking Challenge – Controlling Satellite Payload Task Scheduling

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Interesting Hack-A-Sat Satellite Hacking Challenge - Controlling Satellite Payload Task Scheduling

National space security is an expression of national security in the space domain. With the increasing application of space technology in various fields such as politics, economics, military, and culture, space has become one of the lifelines for national survival and development, embodying enormous national interests, and the importance of space security is becoming increasingly … Read more

Understanding the Linux Kernel

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Understanding the Linux Kernel

Author: aurelianliu Refer to scheduling, memory, files, networks, etc., encountered during work. 1. OS Running States X86 architecture, user mode runs in ring3, kernel mode runs in ring0, two privilege levels. (1) The kernel and some privileged instructions, such as filling page tables, switching process environments, etc., generally operate in ring0. Kernel mode includes the … Read more