diff options
| -rw-r--r-- | host/include/uhd/utils/CMakeLists.txt | 3 | ||||
| -rw-r--r-- | host/include/uhd/utils/atomic.hpp | 143 |
2 files changed, 145 insertions, 1 deletions
diff --git a/host/include/uhd/utils/CMakeLists.txt b/host/include/uhd/utils/CMakeLists.txt index 5a434fd9a..de91993fe 100644 --- a/host/include/uhd/utils/CMakeLists.txt +++ b/host/include/uhd/utils/CMakeLists.txt @@ -1,5 +1,5 @@ # -# Copyright 2010-2011 Ettus Research LLC +# Copyright 2010-2012 Ettus Research LLC # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by @@ -19,6 +19,7 @@ INSTALL(FILES algorithm.hpp assert_has.hpp assert_has.ipp + atomic.hpp byteswap.hpp byteswap.ipp csv.hpp diff --git a/host/include/uhd/utils/atomic.hpp b/host/include/uhd/utils/atomic.hpp new file mode 100644 index 000000000..f9bc728cc --- /dev/null +++ b/host/include/uhd/utils/atomic.hpp @@ -0,0 +1,143 @@ +// +// Copyright 2012 Ettus Research LLC +// +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program. If not, see <http://www.gnu.org/licenses/>. +// + +#ifndef INCLUDED_UHD_UTILS_ATOMIC_HPP +#define INCLUDED_UHD_UTILS_ATOMIC_HPP + +#include <uhd/config.hpp> +#include <uhd/types/time_spec.hpp> +#include <boost/thread/thread.hpp> +#include <boost/interprocess/detail/atomic.hpp> + +namespace uhd{ + + //! A 32-bit integer that can be atomically accessed + class UHD_API atomic_uint32_t{ + public: + + //! Create a new atomic 32-bit integer, initialized to zero + UHD_INLINE atomic_uint32_t(void){ + this->write(0); + } + + //! Compare with cmp, swap with newval if same, return old value + UHD_INLINE boost::uint32_t cas(boost::uint32_t newval, boost::uint32_t cmp){ + return boost::interprocess::detail::atomic_cas32(&_num, newval, cmp); + } + + //! Sets the atomic integer to a new value + UHD_INLINE void write(const boost::uint32_t newval){ + boost::interprocess::detail::atomic_write32(&_num, newval); + } + + //! Gets the current value of the atomic integer + UHD_INLINE boost::uint32_t read(void){ + return boost::interprocess::detail::atomic_read32(&_num); + } + + //! Increment by 1 and return the old value + UHD_INLINE boost::uint32_t inc(void){ + return boost::interprocess::detail::atomic_inc32(&_num); + } + + //! Decrement by 1 and return the old value + UHD_INLINE boost::uint32_t dec(void){ + return boost::interprocess::detail::atomic_dec32(&_num); + } + + private: volatile boost::uint32_t _num; + }; + + /*! + * A reusable barrier to sync multiple threads. + * All threads spin on wait() until count is reset. + */ + class UHD_API reusable_barrier{ + public: + + //! Resize the barrier for N threads + void resize(const size_t size){ + _size = size; + _count.write(size); + } + + //! Wait on the barrier condition + UHD_INLINE void wait(void){ + _count.dec(); + _count.cas(_size, 0); + while (_count.read() != _size){ + boost::this_thread::interruption_point(); + boost::this_thread::yield(); + } + } + + private: + size_t _size; + atomic_uint32_t _count; + }; + + /*! + * Spin-wait on a condition with a timeout. + * \param cond an atomic variable to compare + * \param value compare to atomic for true/false + * \param timeout the timeout in seconds + * \return true for cond == value, false for timeout + */ + UHD_INLINE bool spin_wait_with_timeout( + atomic_uint32_t &cond, + boost::uint32_t value, + const double timeout + ){ + if (cond.read() == value) return true; + const time_spec_t exit_time = time_spec_t::get_system_time() + time_spec_t(timeout); + while (cond.read() != value){ + if (time_spec_t::get_system_time() > exit_time) return false; + boost::this_thread::interruption_point(); + boost::this_thread::yield(); + } + return true; + } + + /*! + * Claimer class to provide synchronization for multi-thread access. + * Claiming enables buffer classes to be used with a buffer queue. + */ + class simple_claimer{ + public: + simple_claimer(void){ + this->release(); + } + + UHD_INLINE void release(void){ + _locked.write(0); + } + + UHD_INLINE bool claim_with_wait(const double timeout){ + if (spin_wait_with_timeout(_locked, 0, timeout)){ + _locked.write(1); + return true; + } + return false; + } + + private: + atomic_uint32_t _locked; + }; + +} //namespace uhd + +#endif /* INCLUDED_UHD_UTILS_ATOMIC_HPP */ |