Elixir's BEAM VM: Busy Waiting – Optimization or Resource Hog?
2025-03-29
Benchmarking Go, Elixir, and Node.js revealed Elixir (on the BEAM VM) exhibited high CPU usage despite excellent responsiveness. The culprit? Busy waiting, a BEAM optimization maximizing responsiveness. While misleading OS-reported CPU usage, enabling busy waiting is beneficial for HTTP workloads on dedicated hardware. However, disabling it is recommended on systems sharing kernels with other software or cloud burstable instances to prevent impacting other processes. Tests showed no performance difference with busy waiting disabled for HTTP requests.
Development
Busy Waiting