OhMyThreads.jl is a Julia package providing user-friendly tools for task-based multithreaded calculations. It offers both a higher-order functions API (tmapreduce, treduce, tmap, etc.) and a macro API (@tasks for ... end) similar to Base.Threads' @threads. The package features multiple schedulers (Dynamic, Static, Greedy, Serial) for controlling work distribution, task-local storage mechanisms for efficient parallel computation, and protections against common multithreading pitfalls like boxed variable capture. The architecture is modular with separate modules for implementation, schedulers, tools, and types.
Qthreads is a user-level threading library designed for high-performance computing (HPC) environments. It provides lightweight, stackful coroutines (qthreads) that are scheduled across 'shepherds' (groups of workers) with topology-aware affinity via hwloc. The library's core synchronization model is the full/empty bit (FEB) on every aligned word, enabling efficient producer-consumer and data-flow patterns. It includes lock-free data structures (queues, hash maps, distributed arrays), parallel loop constructs, and algorithmic skeletons (allpairs, wavefront). The codebase is heavily research-oriented, with multiple scheduler backends (nemesis, sherwood, distrib) and synchronization primitives (sincs, barriers, syncvars). While the architecture is sophisticated and demonstrates deep knowledge of parallel systems, it shows signs of academic evolution: multiple implementations of similar concepts, conditional compilation for optional lock-free paths, and some dead or incomplete code. The library is primarily targeted at HPC applications needing fine-grained task parallelism and is used in benchmarks like UTS (unbalanced tree search) and HPCCG.