[dosshell]

Some context:

Fiber is a datastructure where the execution context is saved. Eg. registers (including instruction pointer) and stack etc. That is a fiber: data.

You normally use a threadpool, core pinned, to execute these fibers.

Since you jump in userspace, you more or less only have to pay for cache misses.

There are many upsides of designing a program using fibers. The major downside i see is that you can not blindly trust mutex and semaphores any longer - since the fiber can change execution thread while yielding/waiting for condition.