2d79ce67a0
Make condition_variable::wait_until() and wait_for() consistently use 'lk' instead of 'lt' because explanations only describe 'lk'. Explain condition_variable::wait(), wait_until() and wait_for() Precondition. Distinguish values returned by wait_until(), wait_for() overloads with and without predicates. Update request for section concerning algorithm, set_scheduling_algorithm(), round_robin and round_robin_ws. Clarify lifespan implications of fiber_group::add_fiber(). Explain requirement for a heap fiber object. Experiment with cross-reference links to other Boost libraries.
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.
Buiding: Detailed instructions can be found at https://svn.boost.org/trac/boost/wiki/TryModBoost.
git clone http://github.com/boostorg/boost modular-boost
cd modular-boost
git submodule update --init
cd libs
git clone http://github.com/olk/boost-fiber fiber
cd ..
cmake -P forward_headers.cmake
./bootstrap.sh
cp b2 /usr/local/bin
cd libs/fiber/test
b2