Beyond Sequential Consistency - Leveraging Atomics for Fun & Profit - Christopher Fretz C++Now 2025

https://www.cppnow.org​ --- Beyond Sequential Consistency - Leveraging Atomics for Fun and Profit - Christopher Fretz - C++Now 2025 --- In 2011, C++ introduced a formally defined memory model, providing a foundation for portable, multi-threaded code with well-defined correctness guarantees. This was a major milestone, enabling expressive threading primitives and safe concurrency patterns while allowing low-level optimizations for performance. By default, C++ atomics enforce sequential consistency, which ensures intuitive, predictable behavior. However, these strong guarantees often exceed what’s necessary for correctness and come with a performance cost. This talk delves into weaker memory orderings, particularly acquire/release and relaxed semantics, using a ring buffer as a practical example of how they can be used. We’ll also examine how the C++ memory model maps to real hardware, focusing on x86’s native guarantees, and comparing against less coherent platforms like ARM. We'll explore how strategic use of weaker synchronization can unlock significant performance gains without sacrificing correctness. --- Slides: https://github.com/boostcon/cppnow_pr... Join think-cell as a C++ Developer and work on cutting-edge challenges with a focus on code excellence, innovation, and working alongside an international team of experts — apply now to be part of a team shaping the future of business presentations. https://www.think-cell.com/en/career --- Christopher Fretz Chris is a senior C++ engineer working at Bloomberg LP on a developer experience team for a large organization within the company's market data pipeline. Chris has 8 years of experience working professionally with C++ and has worked on a wide breadth of projects, from low-latency stream processing, to lock free data structure design, to DevX and build system orchestration. --- C++Now 2026 - 27th April - 1st May C++Now is an annual onsite international C++ programming and coding conference held in Aspen, Colarado. For all C++ developers, C++ software engineers and those involved with the C++ language, CppNow provides an indepth and technical content provided by the best and brightest C++ experts of the C++ world. Annual CppNow Conference - https://www.cppnow.org   / cppnow​     / cppnow     / cppnow     / cppnow   https://mastodon.social/@cppnow Video Sponsors: think-cell and Bloomberg --- Videos Filmed & Edited By Bash Films: https://bashfilms.com/ YouTube Channel Managed & Optimized By Digital Medium Ltd: https://events.digital-medium.co.uk --- #performance #atomic #boost #cpp #cplusplus #programming #coding #softwareengineering #softwaredeveloper #code #cplusplusprogramming #cplusplustutorial #cplus #softwaredevelopment