1e751d7dbf
- Change some doc references from 'algorithm' to 'sched_algorithm'. - Initial cut at supporting arbitrary user-coded scheduler properties. - Set fiber_properties::sched_algo_ every time through awakened(). - Define sched_algorithm methods on fiber_base*, not worker_fiber*. - Simplify detail::fifo by making tail_ point to last link pointer. - Reimplement waiting_queue::push() using pointer-to-pointer trick. - Reimplement waiting_queue::move_to() using fiber_base** scan. - Make bounded_queue::tail_ a ptr* to simplify appending new nodes. - Make unbounded_queue::tail_ a ptr* to simplify linking new nodes. - Remove thread_affinity flag and access methods. - Re-add thread_affinity specific to workstealing_round_robin. - Remove 'priority' for every fiber, and its support methods.
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.