问题
In Tarantool, are fibers used when the Lua code author wants Tarantool to schedule the execution? Are co-routines (in the Tarantool/LuaJIT process) used when the Lua code author wants to be in control of the execution?
回答1:
In Tarantool, fibers are synonymous with coroutines. The fibers are more integrated to Tarantool I/O etc, you should use them instead of lua coroutines. We suggest you always use our fibers, rather than Lua coroutines, since they are more powerful. Our entire I/O stack is integrated with them: sockets, files, net.box, mysql, postgresql, etc.
Link to docs: http://tarantool.org/doc/reference/fiber.html
There are some tasks that coroutines could be used for, like iterators. It is perfectly valid to use both coroutines and fibers simultaneously but that may cause a confusion. Coroutine yield may fail with an infamous attempt to yield across C-call boundary, while fibers work in this situation.
回答2:
Fiber stack is larger than one of a coroutine. It's mmapp'ed to 64KB, and is at least one OS page (4KB usually). Fiber context switching incurs extra overhead, since it hides/restores registers in addition to hiding/restoring the coroutine. Fiber context switches break JIT in LuaJIT, since LuaJIT is not able to hide/restore traced execution. Unlike coroutines, fibers work well with all non-blocking IO which is built into the application server: whenver a fiber yields implicitly on a IO call, another fiber kicks in. But not another coroutine, of course, you'll have to take care of this yourself if you're using them.
来源：https://stackoverflow.com/questions/36152489/when-to-use-fibers-and-when-to-use-co-routines-in-tarantool