I started writing an article on the internals of context switching implementation in Linux and ended up writing almost 50 pages before I realized this

Linux Context Switching Internals: Process State and Memory

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2024-12-30 23:00:06

I started writing an article on the internals of context switching implementation in Linux and ended up writing almost 50 pages before I realized this is almost a book’s worth of work.

I am launching this as an early-release PDF book and a series of articles on this Substack. This first article is free, while the future ones will be for paid subscribers. The complete book may have 4-5 total chapters, totalling about 80-90 pages.

I will send out a separate email to existing paid subscribers with the discount code. New paid subscribers, please reach out to me after upgrade.

Context switching is necessary for a high-throughput and responsive system where all processes make progress despite limited execution resources. But, as we discussed in the previous article, it also has performance costs which cascade through various indirect mechanisms, such as cache and TLB eviction.

When building performance-critical systems or debugging performance issues due to context switching, it becomes important to understand the internal implementation details to be able to reason through the performance issues and possibly mitigate them. Not only that, it leads you to learn many low-level details about the hardware architecture, and makes you realize why the kernel is so special.