--- title: Writing mutexes from scratch in Go | daily.dev description: Mutexes (locks) ensure only one thread executes critical code sections at a time. This guide implements several mutex variants in Go from scratch: a naive spin... canonical: https://daily.dev/posts/fs9czqfvm twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Writing mutexes from scratch in Go | daily.dev og:description: Mutexes (locks) ensure only one thread executes critical code sections at a time. This guide implements several mutex variants in Go from scratch: a naive spin... og:url: https://daily.dev/posts/fs9czqfvm og:image: https://api.daily.dev/og/posts/Fs9CzqFVm.png og:image:alt: Post cover image og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Writing mutexes from scratch in Go **[Go Developers](https://daily.dev/sources/golangnuts)** · [@func25](https://daily.dev/func25) · 3 upvotes · 0 comments ## Summary Mutexes (locks) ensure only one thread executes critical code sections at a time. This guide implements several mutex variants in Go from scratch: a naive spin lock with race conditions, a working spin lock using atomic operations, and a futex-based lock leveraging OS primitives for efficiency. Each implementation explores performance tradeoffs—spin locks waste CPU cycles busy-waiting, while futex locks use syscalls to sleep threads. An adaptive approach combines spinning briefly before sleeping, balancing latency and CPU usage. Benchmarks compare custom implementations against Go's sync.Mutex across different contention scenarios, revealing how design choices affect real-world performance. ## Full article daily.dev links to this article rather than hosting it. 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