eve.rt.fiber.pool

Fiber Pool — Reusable Fiber Stacks for High-Concurrency Servers

This module provides FiberPool, a class that maintains a pool of reusable fibers. Creating and destroying fibers is expensive because each allocates a stack (typically 64 KB on POSIX). The pool amortises this cost by keeping finished fibers alive and re-dispatching them through a trampoline loop.

Lifecycle of a pooled fiber:

1. spawn(work) creates a fiber whose trampoline reads

   slot.work, executes it, returns the slot to the free list, and then parks (yield without re-queue).

2. The next spawn() call takes the slot from the free list,

   sets slot.work, and un-parks the fiber so the trampoline runs again.

Thread affinity: one pool per FiberScheduler, one scheduler per event loop, one event loop per thread.

Example:

auto loop  = EventLoop.create();
auto sched = new FiberScheduler(loop);
sched.attachToLoop();

auto pool = new FiberPool(sched, 16, 1024);
scope (exit) pool.dispose();

server.onAccept = (ref TcpListener s, Handle h) {
   pool.spawn(() @trusted {
      auto sock = FiberSocket.adopt(sched, *sched.eventLoop, h);
      handleRequest(sock);
      sock.dispose();
   });
};

loop.run();