finethread

Finethread refers to a class of extremely lightweight user-space threads intended for fine-grained concurrency. It is commonly implemented as fibers or coroutines and scheduled in user space by a runtime, in contrast to kernel-managed OS threads. This approach reduces per-thread resource usage and the cost of context switches, enabling high levels of concurrency within a single process.

Finethread models can be cooperative, where tasks yield control voluntarily, or preemptive, where the scheduler interrupts tasks. They may be stackful, keeping a full separate call stack for each thread, or stackless, where the state is kept in heap-allocated frames or closures. Implementations typically provide operations to yield or resume execution, and to cancel or join tasks. In practice, finethreads appear in libraries and language runtimes through coroutines, green threads, and async frameworks.

Advantages include lower memory overhead per thread, reduced context-switch latency, and better cache locality, which collectively improve scalability for fine-grained tasks. Drawbacks include debugging difficulty, obstacles with blocking I/O, and the need for careful scheduler design to avoid starvation or priority inversion. Finethread is not a universal replacement for OS threads; for tasks requiring true parallelism or kernel resources, native threads or processes are still appropriate, and finethread is often used alongside them.

Common use cases are high-throughput network servers, game engines, real-time simulations, and data processing pipelines that handle many concurrent units of work. See also: fibers, coroutines, green threads, user-space threading, cooperative multitasking.