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lammps/lib/kokkos/core/src/Kokkos_Threads.hpp
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Kokkos_Threads.hpp
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/*
//@HEADER
// ************************************************************************
//
// Kokkos v. 2.0
// Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact H. Carter Edwards (hcedwar@sandia.gov)
//
// ************************************************************************
//@HEADER
*/
#ifndef KOKKOS_THREADS_HPP
#define KOKKOS_THREADS_HPP
#include <Kokkos_Core_fwd.hpp>
#if defined( KOKKOS_HAVE_PTHREAD )
#include <cstddef>
#include <iosfwd>
#include <Kokkos_HostSpace.hpp>
#include <Kokkos_ScratchSpace.hpp>
#include <Kokkos_Layout.hpp>
#include <Kokkos_MemoryTraits.hpp>
#include <impl/Kokkos_Tags.hpp>
/*--------------------------------------------------------------------------*/
namespace Kokkos {
namespace Impl {
class ThreadsExec ;
} // namespace Impl
} // namespace Kokkos
/*--------------------------------------------------------------------------*/
namespace Kokkos {
/** \brief Execution space for a pool of Pthreads or C11 threads on a CPU. */
class Threads {
public:
//! \name Type declarations that all Kokkos devices must provide.
//@{
//! Tag this class as a kokkos execution space
typedef Threads execution_space ;
typedef Kokkos::HostSpace memory_space ;
//! This execution space preferred device_type
typedef Kokkos::Device<execution_space,memory_space> device_type;
typedef Kokkos::LayoutRight array_layout ;
typedef memory_space::size_type size_type ;
typedef ScratchMemorySpace< Threads > scratch_memory_space ;
//@}
/*------------------------------------------------------------------------*/
//! \name Static functions that all Kokkos devices must implement.
//@{
/// \brief True if and only if this method is being called in a
/// thread-parallel function.
static int in_parallel();
/** \brief Set the device in a "sleep" state.
*
* This function sets the device in a "sleep" state in which it is
* not ready for work. This may consume less resources than if the
* device were in an "awake" state, but it may also take time to
* bring the device from a sleep state to be ready for work.
*
* \return True if the device is in the "sleep" state, else false if
* the device is actively working and could not enter the "sleep"
* state.
*/
static bool sleep();
/// \brief Wake the device from the 'sleep' state so it is ready for work.
///
/// \return True if the device is in the "ready" state, else "false"
/// if the device is actively working (which also means that it's
/// awake).
static bool wake();
/// \brief Wait until all dispatched functors complete.
///
/// The parallel_for or parallel_reduce dispatch of a functor may
/// return asynchronously, before the functor completes. This
/// method does not return until all dispatched functors on this
/// device have completed.
static void fence();
/// \brief Free any resources being consumed by the device.
///
/// For the Threads device, this terminates spawned worker threads.
static void finalize();
/// \brief Print configuration information to the given output stream.
static void print_configuration( std::ostream & , const bool detail = false );
//@}
/*------------------------------------------------------------------------*/
/*------------------------------------------------------------------------*/
//! \name Space-specific functions
//@{
/** \brief Initialize the device in the "ready to work" state.
*
* The device is initialized in a "ready to work" or "awake" state.
* This state reduces latency and thus improves performance when
* dispatching work. However, the "awake" state consumes resources
* even when no work is being done. You may call sleep() to put
* the device in a "sleeping" state that does not consume as many
* resources, but it will take time (latency) to awaken the device
* again (via the wake()) method so that it is ready for work.
*
* Teams of threads are distributed as evenly as possible across
* the requested number of numa regions and cores per numa region.
* A team will not be split across a numa region.
*
* If the 'use_' arguments are not supplied the hwloc is queried
* to use all available cores.
*/
static void initialize( unsigned threads_count = 0 ,
unsigned use_numa_count = 0 ,
unsigned use_cores_per_numa = 0 ,
bool allow_asynchronous_threadpool = false );
static int is_initialized();
/** \brief Return the maximum amount of concurrency. */
static int concurrency();
static Threads & instance( int = 0 );
//----------------------------------------
static int thread_pool_size( int depth = 0 );
#if defined( KOKKOS_ACTIVE_EXECUTION_MEMORY_SPACE_HOST )
static int thread_pool_rank();
#else
KOKKOS_INLINE_FUNCTION static int thread_pool_rank() { return 0 ; }
#endif
inline static unsigned max_hardware_threads() { return thread_pool_size(0); }
KOKKOS_INLINE_FUNCTION static unsigned hardware_thread_id() { return thread_pool_rank(); }
//@}
//----------------------------------------
};
} // namespace Kokkos
/*--------------------------------------------------------------------------*/
namespace Kokkos {
namespace Impl {
template<>
struct VerifyExecutionCanAccessMemorySpace
< Kokkos::Threads::memory_space
, Kokkos::Threads::scratch_memory_space
>
{
enum { value = true };
inline static void verify( void ) { }
inline static void verify( const void * ) { }
};
} // namespace Impl
} // namespace Kokkos
/*--------------------------------------------------------------------------*/
#include <Kokkos_ExecPolicy.hpp>
#include <Kokkos_Parallel.hpp>
#include <Threads/Kokkos_ThreadsExec.hpp>
#include <Threads/Kokkos_ThreadsTeam.hpp>
#include <Threads/Kokkos_Threads_Parallel.hpp>
#include <KokkosExp_MDRangePolicy.hpp>
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
#endif /* #if defined( KOKKOS_HAVE_PTHREAD ) */
#endif /* #define KOKKOS_THREADS_HPP */
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