The Danger of Atomic Operations

By Ashley Hedberg, Software Engineer

The C++ Standard provides a library for performing fine-grained atomic operations (e.g. std::atomic). Engineers sometimes reach for these atomic operations in the hope to introduce some lock-free mechanism, or to introduce clever tricks to improve performance. At Google, we’ve found – more often than not – that such attempts lead to code that is difficult to get right, hard to understand, and can often introduce subtle and sometimes dangerous bugs.

We’ve now published a guide on the danger of these atomic operations, and are publishing it to Abseil as a general programming guide. Atomic operations should be used only in a handful of low-level data structures which are written by a few experts and then reviewed and tested thoroughly. Most programmers make mistakes when they attempt direct use of atomic operations. Even when they don’t, the resulting code is hard for others to maintain.

For more information, check out The Danger of Atomic Operations.