FPUtilstander

FPUtilstander is an open-source, cross-platform utility designed to observe and analyze workloads in functional programming environments. It provides lightweight instrumentation, performance profiling, and runtime tracing for programs written in functional languages, allowing developers to collect metrics and event data with minimal source changes. It can attach to a running process or launch a program under controlled instrumentation, reporting call activity, memory usage, and timing information.

Key features:

- Low-overhead tracing

- Automatic function entry/exit logging and stack sampling

- Pluggable backends (JSON, CSV, InfluxDB)

- Call graph generation and flame graphs

- Memory and allocation accounting

- Cross-language compatibility with FP runtimes (Haskell, OCaml, F#, Scala)

- Agent mode for attaching to running processes

- Sandbox mode to constrain side effects

- CI/CD integration and test harnesses

FPUtilstander’s architecture comprises a core tracer library, a lightweight agent, and a set of adapters for storage backends. Communication uses a compact protocol over IPC or sockets, with optional sampling to minimize overhead. The design emphasizes safety in probing functional code, offering sandboxing options and a clear separation between instrumentation and business logic.

History guides and development have shaped FPUtilstander into a practical tool for researchers and engineers. The project originated in 2015 as a community tool for studying functional performance. The first public release appeared in 2016, followed by periodic rewrites and major upgrades. The 2.x series, released in 2020–2023, introduced modular adapters and improved multi-language support.

FPUtilstander is available under the MIT License. The project is hosted on GitHub with active issue tracking, documentation, and tutorials.