fiber/examples/migration/workstealing_round_robin.cpp

//          Copyright Oliver Kowalke 2013.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)

#include "workstealing_round_robin.hpp"

#include <boost/assert.hpp>

#ifdef BOOST_HAS_ABI_HEADERS
#  include BOOST_ABI_PREFIX
#endif

void
workstealing_round_robin::awakened( boost::fibers::detail::fiber_handle f)
{
    std::unique_lock< std::mutex > lk( mtx_);
    rqueue_.push_back( f);
}

boost::fibers::detail::fiber_handle
workstealing_round_robin::pick_next()
{
    std::unique_lock< std::mutex > lk( mtx_);
    boost::fibers::detail::fiber_handle f;
    if ( ! rqueue_.empty() )
    {
        f = rqueue_.front();
        rqueue_.pop_front();
    }
    return f;
}

void
workstealing_round_robin::priority( boost::fibers::detail::fiber_handle f, int prio) noexcept
{
    BOOST_ASSERT( f);

    // set only priority to fiber
    // round-robin does not respect priorities
    f->priority( prio);
}

boost::fibers::fiber
workstealing_round_robin::steal()
{
    std::unique_lock< std::mutex > lk( mtx_);
    for ( boost::fibers::detail::fiber_handle f : rqueue_)
    {
        if ( ! f->thread_affinity() )
        {
            rqueue_.remove( f);
            return boost::fibers::fiber( f);
        }
    }
    return boost::fibers::fiber();
}

#ifdef BOOST_HAS_ABI_HEADERS
#  include BOOST_ABI_SUFFIX
#endif