Building a Fast Lock-Free Queue in Modern C++ from Scratch

Summary

22 May 2026 Building a Fast Lock-Free Queue in Modern C++ From Scratch For those just interested in the code you can find it here and if you want to see it action in an actual project you can check this out! Now to set the context for those who might be new to this, typically a Queue is one of the most fundamental data structures in computer science, and it is used everywhere in software development. A queue is a simple first-in-first-out (FIFO) structure where you can Push items to the back and Pop items from the front. In single-threaded code, there are already implementations in most standard libraries, for instance in C++ its std::queue, and even implement it from sratch is pretty trivial. So why all the trouble you ask? Its simply because when we move over to a multi threaded environemnt(a typical requirement for a whole lot of real world applications), the whole thing becomes a whole lot more complex, now you have multiple threads contending or fighting for the data in your queue, and if you dont manage it properly you get the classical Undefined Behaviour, that is one theads makes some chnages while another tires to read causing all sort of corruptions. Now before you proceed, its very important to ask yourself, Do you reallly need a fast lock-free queue? Then answer is for most applications you typically dont. You are all good with typicall mutex based synchronizatons you can add on a regular queue. However, once you start dealing with more demanding things like high frequency trading systems, real time game engines, audio synthesis pipelines, massive data ingestion systems, or any situtuation where you got a large number of threads trying to communicate, the performance of the queue suddenly starts mattering a lot. In these systems even a fraction of a millisecond of delay in one queue operation cascades into stuttering audio, dropped frames, missed trades, or just an overall sluggish system. So we really do want our queue to be fast, ideally something that...