ed64ee77f8
Instead of setting a fiber_properties subclass's sched_algo_ back pointer once at construction time, unconditionally set it every time that fiber becomes READY (and is therefore passed to sched_algorithm::awakened()). This handles the case in which that fiber migrates to a different thread with a different sched_algorithm subclass instance. Break out fiber_properties::notify() implementation to a separate .cpp implementation file so it can bring in algorithm.hpp. We don't want properties.hpp to depend on algorithm.hpp.
boost.fiber
boost.fiber provides a framework for micro-/userland-threads (fibers) scheduled cooperativly. The API contains classes and functions to manage and synchronize fibers similiar to boost.thread.
A fiber is able to store the current execution state, including all registers and CPU flags, the instruction pointer, and the stack pointer and later restore this state. The idea is to have multiple execution paths running on a single thread using a sort of cooperative scheduling (threads are preemptively scheduled) - the running fiber decides explicitly when its yields to allow another fiber to run (context switching).
A context switch between threads costs usally thousends of CPU cycles on x86 compared to a fiber switch with less than 100 cycles. A fiber can only run on a single thread at any point in time.
Building: Detailed instructions can be found at https://svn.boost.org/trac/boost/wiki/TryModBoost.