State of futex2
summary
A new futex2 syscall family actually adds specific operations rather than overloading one call: merged in Linux 5.16 is a dedicated syscall that implements wait on multiple futexes for Windows-style WaitForMultipleObjects use cases. Prototype shows lower CPU and kernel load for many waiters (used by Steam Proton and some game engines), similar per-call latency to existing futexes, planned variable-size futex support, and ongoing design work to add NUMA hints; PI and fd-based wait integration are not implemented.
AI-written summary · about
chapters (6)
- 0:00Introduction to futex
- 1:21How futex works
- 4:21Need for a new API
- 8:29Advanced features and scaling
- 10:54Remaining challenges
- 12:52Q&A and concluding remarks
