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Kokkos_ExecPolicy.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,
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// met:
//
// 1. Redistributions of source code must retain the above copyright
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// documentation and/or other materials provided with the distribution.
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// 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.
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// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef KOKKOS_EXECPOLICY_HPP
#define KOKKOS_EXECPOLICY_HPP
#include <Kokkos_Core_fwd.hpp>
#include <impl/Kokkos_Traits.hpp>
#include <impl/Kokkos_StaticAssert.hpp>
#include <impl/Kokkos_Tags.hpp>
//----------------------------------------------------------------------------
namespace Kokkos {
/** \brief Execution policy for work over a range of an integral type.
*
* Valid template argument options:
*
* With a specified execution space:
* < ExecSpace , WorkTag , { IntConst | IntType } >
* < ExecSpace , WorkTag , void >
* < ExecSpace , { IntConst | IntType } , void >
* < ExecSpace , void , void >
*
* With the default execution space:
* < WorkTag , { IntConst | IntType } , void >
* < WorkTag , void , void >
* < { IntConst | IntType } , void , void >
* < void , void , void >
*
* IntType is a fundamental integral type
* IntConst is an Impl::integral_constant< IntType , Blocking >
*
* Blocking is the granularity of partitioning the range among threads.
*/
template< class Arg0 = void , class Arg1 = void , class Arg2 = void
, class ExecSpace =
// The first argument is the execution space,
// otherwise use the default execution space.
typename std::conditional
< Impl::is_execution_space< Arg0 >::value , Arg0
, Kokkos::DefaultExecutionSpace >::type
>
class RangePolicy {
private:
// Default integral type and blocking factor:
typedef int DefaultIntType ;
enum { DefaultIntValue = 8 };
enum { Arg0_Void = Impl::is_same< Arg0 , void >::value };
enum { Arg1_Void = Impl::is_same< Arg1 , void >::value };
enum { Arg2_Void = Impl::is_same< Arg2 , void >::value };
enum { Arg0_ExecSpace = Impl::is_execution_space< Arg0 >::value };
enum { Arg0_IntConst = Impl::is_integral_constant< Arg0 >::value };
enum { Arg1_IntConst = Impl::is_integral_constant< Arg1 >::value };
enum { Arg2_IntConst = Impl::is_integral_constant< Arg2 >::value };
enum { Arg0_IntType = Impl::is_integral< Arg0 >::value };
enum { Arg1_IntType = Impl::is_integral< Arg1 >::value };
enum { Arg2_IntType = Impl::is_integral< Arg2 >::value };
enum { Arg0_WorkTag = ! Arg0_ExecSpace && ! Arg0_IntConst && ! Arg0_IntType && ! Arg0_Void };
enum { Arg1_WorkTag = Arg0_ExecSpace && ! Arg1_IntConst && ! Arg1_IntType && ! Arg1_Void };
enum { ArgOption_OK = Impl::StaticAssert< (
( Arg0_ExecSpace && Arg1_WorkTag && ( Arg2_IntConst || Arg2_IntType ) ) ||
( Arg0_ExecSpace && Arg1_WorkTag && Arg2_Void ) ||
( Arg0_ExecSpace && ( Arg1_IntConst || Arg1_IntType ) && Arg2_Void ) ||
( Arg0_ExecSpace && Arg1_Void && Arg2_Void ) ||
( Arg0_WorkTag && ( Arg1_IntConst || Arg1_IntType ) && Arg2_Void ) ||
( Arg0_WorkTag && Arg1_Void && Arg2_Void ) ||
( ( Arg0_IntConst || Arg0_IntType ) && Arg1_Void && Arg2_Void ) ||
( Arg0_Void && Arg1_Void && Arg2_Void )
) >::value };
// The work argument tag is the first or second argument
typedef typename std::conditional< Arg0_WorkTag , Arg0 ,
typename std::conditional< Arg1_WorkTag , Arg1 , void
>::type >::type
WorkTag ;
enum { Granularity = Arg0_IntConst ? unsigned(Impl::is_integral_constant<Arg0>::integral_value) : (
Arg1_IntConst ? unsigned(Impl::is_integral_constant<Arg1>::integral_value) : (
Arg2_IntConst ? unsigned(Impl::is_integral_constant<Arg2>::integral_value) : (
unsigned(DefaultIntValue) ))) };
// Only accept the integral type if the blocking is a power of two
static_assert( Impl::is_integral_power_of_two( Granularity )
, "RangePolicy blocking granularity must be power of two" );
typedef typename std::conditional< Arg0_IntType , Arg0 ,
typename std::conditional< Arg1_IntType , Arg1 ,
typename std::conditional< Arg2_IntType , Arg2 ,
typename std::conditional< Arg0_IntConst , typename Impl::is_integral_constant<Arg0>::integral_type ,
typename std::conditional< Arg1_IntConst , typename Impl::is_integral_constant<Arg1>::integral_type ,
typename std::conditional< Arg2_IntConst , typename Impl::is_integral_constant<Arg2>::integral_type ,
DefaultIntType
>::type >::type >::type
>::type >::type >::type
IntType ;
enum { GranularityMask = IntType(Granularity) - 1 };
ExecSpace m_space ;
IntType m_begin ;
IntType m_end ;
public:
//! Tag this class as an execution policy
typedef ExecSpace execution_space ;
typedef RangePolicy execution_policy ;
typedef WorkTag work_tag ;
typedef IntType member_type ;
KOKKOS_INLINE_FUNCTION const execution_space & space() const { return m_space ; }
KOKKOS_INLINE_FUNCTION member_type begin() const { return m_begin ; }
KOKKOS_INLINE_FUNCTION member_type end() const { return m_end ; }
inline RangePolicy() : m_space(), m_begin(0), m_end(0) {}
/** \brief Total range */
inline
RangePolicy( const member_type work_begin
, const member_type work_end
)
: m_space()
, m_begin( work_begin < work_end ? work_begin : 0 )
, m_end( work_begin < work_end ? work_end : 0 )
{}
/** \brief Total range */
inline
RangePolicy( const execution_space & work_space
, const member_type work_begin
, const member_type work_end
)
: m_space( work_space )
, m_begin( work_begin < work_end ? work_begin : 0 )
, m_end( work_begin < work_end ? work_end : 0 )
{}
/** \brief Subrange for a partition's rank and size.
*
* Typically used to partition a range over a group of threads.
*/
struct WorkRange {
typedef typename RangePolicy::work_tag work_tag ;
typedef typename RangePolicy::member_type member_type ;
KOKKOS_INLINE_FUNCTION member_type begin() const { return m_begin ; }
KOKKOS_INLINE_FUNCTION member_type end() const { return m_end ; }
/** \brief Subrange for a partition's rank and size.
*
* Typically used to partition a range over a group of threads.
*/
KOKKOS_INLINE_FUNCTION
WorkRange( const RangePolicy & range
, const int part_rank
, const int part_size
)
: m_begin(0), m_end(0)
{
if ( part_size ) {
// Split evenly among partitions, then round up to the granularity.
const member_type work_part =
( ( ( ( range.end() - range.begin() ) + ( part_size - 1 ) ) / part_size )
+ GranularityMask ) & ~member_type(GranularityMask);
m_begin = range.begin() + work_part * part_rank ;
m_end = m_begin + work_part ;
if ( range.end() < m_begin ) m_begin = range.end() ;
if ( range.end() < m_end ) m_end = range.end() ;
}
}
private:
member_type m_begin ;
member_type m_end ;
WorkRange();
WorkRange & operator = ( const WorkRange & );
};
};
} // namespace Kokkos
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
namespace Kokkos {
namespace Experimental {
/** \brief Scratch memory request accepting per team and per thread value
*
* An instance of this class can be given as the last argument to a
* TeamPolicy constructor. It sets the amount of user requested shared
* memory for the team.
*/
template< class MemorySpace >
class TeamScratchRequest {
size_t m_per_team;
size_t m_per_thread;
public:
TeamScratchRequest(size_t per_team_, size_t per_thread_ = 0):
m_per_team(per_team_), m_per_thread(per_thread_) {
}
size_t per_team() const {
return m_per_team;
}
size_t per_thread() const {
return m_per_thread;
}
size_t total(const size_t team_size) const {
return m_per_team + m_per_thread * team_size;
}
};
}
/** \brief Execution policy for parallel work over a league of teams of threads.
*
* The work functor is called for each thread of each team such that
* the team's member threads are guaranteed to be concurrent.
*
* The team's threads have access to team shared scratch memory and
* team collective operations.
*
* If the WorkTag is non-void then the first calling argument of the
* work functor's parentheses operator is 'const WorkTag &'.
* This allows a functor to have multiple work member functions.
*
* template argument option with specified execution space:
* < ExecSpace , WorkTag >
* < ExecSpace , void >
*
* template argument option with default execution space:
* < WorkTag , void >
* < void , void >
*/
template< class Arg0 = void
, class Arg1 = void
, class ExecSpace =
// If the first argument is not an execution
// then use the default execution space.
typename std::conditional
< Impl::is_execution_space< Arg0 >::value , Arg0
, Kokkos::DefaultExecutionSpace >::type
>
class TeamPolicy {
private:
enum { Arg0_ExecSpace = Impl::is_execution_space< Arg0 >::value };
enum { Arg1_Void = Impl::is_same< Arg1 , void >::value };
enum { ArgOption_OK = Impl::StaticAssert< ( Arg0_ExecSpace || Arg1_Void ) >::value };
typedef typename std::conditional< Arg0_ExecSpace , Arg1 , Arg0 >::type WorkTag ;
public:
//! Tag this class as an execution policy
typedef TeamPolicy execution_policy ;
typedef ExecSpace execution_space ;
typedef WorkTag work_tag ;
//----------------------------------------
/** \brief Query maximum team size for a given functor.
*
* This size takes into account execution space concurrency limitations and
* scratch memory space limitations for reductions, team reduce/scan, and
* team shared memory.
*/
template< class FunctorType >
static int team_size_max( const FunctorType & );
/** \brief Query recommended team size for a given functor.
*
* This size takes into account execution space concurrency limitations and
* scratch memory space limitations for reductions, team reduce/scan, and
* team shared memory.
*/
template< class FunctorType >
static int team_size_recommended( const FunctorType & );
template< class FunctorType >
static int team_size_recommended( const FunctorType & , const int&);
//----------------------------------------
/** \brief Construct policy with the given instance of the execution space */
TeamPolicy( const execution_space & , int league_size_request , int team_size_request , int vector_length_request = 1 );
TeamPolicy( const execution_space & , int league_size_request , const Kokkos::AUTO_t & , int vector_length_request = 1 );
/** \brief Construct policy with the default instance of the execution space */
TeamPolicy( int league_size_request , int team_size_request , int vector_length_request = 1 );
TeamPolicy( int league_size_request , const Kokkos::AUTO_t & , int vector_length_request = 1 );
template<class MemorySpace>
TeamPolicy( int league_size_request , int team_size_request , const Experimental::TeamScratchRequest<MemorySpace>& team_scratch_memory_request );
template<class MemorySpace>
TeamPolicy( int league_size_request , const Kokkos::AUTO_t & , const Experimental::TeamScratchRequest<MemorySpace>& team_scratch_memory_request );
/** \brief The actual league size (number of teams) of the policy.
*
* This may be smaller than the requested league size due to limitations
* of the execution space.
*/
KOKKOS_INLINE_FUNCTION int league_size() const ;
/** \brief The actual team size (number of threads per team) of the policy.
*
* This may be smaller than the requested team size due to limitations
* of the execution space.
*/
KOKKOS_INLINE_FUNCTION int team_size() const ;
/** \brief Parallel execution of a functor calls the functor once with
* each member of the execution policy.
*/
struct member_type {
/** \brief Handle to the currently executing team shared scratch memory */
KOKKOS_INLINE_FUNCTION
typename execution_space::scratch_memory_space team_shmem() const ;
/** \brief Rank of this team within the league of teams */
KOKKOS_INLINE_FUNCTION int league_rank() const ;
/** \brief Number of teams in the league */
KOKKOS_INLINE_FUNCTION int league_size() const ;
/** \brief Rank of this thread within this team */
KOKKOS_INLINE_FUNCTION int team_rank() const ;
/** \brief Number of threads in this team */
KOKKOS_INLINE_FUNCTION int team_size() const ;
/** \brief Barrier among the threads of this team */
KOKKOS_INLINE_FUNCTION void team_barrier() const ;
/** \brief Intra-team reduction. Returns join of all values of the team members. */
template< class JoinOp >
KOKKOS_INLINE_FUNCTION
typename JoinOp::value_type team_reduce( const typename JoinOp::value_type
, const JoinOp & ) const ;
/** \brief Intra-team exclusive prefix sum with team_rank() ordering.
*
* The highest rank thread can compute the reduction total as
* reduction_total = dev.team_scan( value ) + value ;
*/
template< typename Type >
KOKKOS_INLINE_FUNCTION Type team_scan( const Type & value ) const ;
/** \brief Intra-team exclusive prefix sum with team_rank() ordering
* with intra-team non-deterministic ordering accumulation.
*
* The global inter-team accumulation value will, at the end of the
* league's parallel execution, be the scan's total.
* Parallel execution ordering of the league's teams is non-deterministic.
* As such the base value for each team's scan operation is similarly
* non-deterministic.
*/
template< typename Type >
KOKKOS_INLINE_FUNCTION Type team_scan( const Type & value , Type * const global_accum ) const ;
};
};
} // namespace Kokkos
namespace Kokkos {
namespace Impl {
template<typename iType, class TeamMemberType>
struct TeamThreadRangeBoundariesStruct {
private:
KOKKOS_INLINE_FUNCTION static
iType ibegin( const iType & arg_begin
, const iType & arg_end
, const iType & arg_rank
, const iType & arg_size
)
{
return arg_begin + ( ( arg_end - arg_begin + arg_size - 1 ) / arg_size ) * arg_rank ;
}
KOKKOS_INLINE_FUNCTION static
iType iend( const iType & arg_begin
, const iType & arg_end
, const iType & arg_rank
, const iType & arg_size
)
{
const iType end_ = arg_begin + ( ( arg_end - arg_begin + arg_size - 1 ) / arg_size ) * ( arg_rank + 1 );
return end_ < arg_end ? end_ : arg_end ;
}
public:
typedef iType index_type;
const iType start;
const iType end;
enum {increment = 1};
const TeamMemberType& thread;
KOKKOS_INLINE_FUNCTION
TeamThreadRangeBoundariesStruct( const TeamMemberType& arg_thread
, const iType& arg_end
)
: start( ibegin( 0 , arg_end , arg_thread.team_rank() , arg_thread.team_size() ) )
, end( iend( 0 , arg_end , arg_thread.team_rank() , arg_thread.team_size() ) )
, thread( arg_thread )
{}
KOKKOS_INLINE_FUNCTION
TeamThreadRangeBoundariesStruct( const TeamMemberType& arg_thread
, const iType& arg_begin
, const iType& arg_end
)
: start( ibegin( arg_begin , arg_end , arg_thread.team_rank() , arg_thread.team_size() ) )
, end( iend( arg_begin , arg_end , arg_thread.team_rank() , arg_thread.team_size() ) )
, thread( arg_thread )
{}
};
template<typename iType, class TeamMemberType>
struct ThreadVectorRangeBoundariesStruct {
typedef iType index_type;
enum {start = 0};
const iType end;
enum {increment = 1};
KOKKOS_INLINE_FUNCTION
ThreadVectorRangeBoundariesStruct (const TeamMemberType& thread, const iType& count):
end( count )
{}
};
template<class TeamMemberType>
struct ThreadSingleStruct {
const TeamMemberType& team_member;
KOKKOS_INLINE_FUNCTION
ThreadSingleStruct(const TeamMemberType& team_member_):team_member(team_member_){}
};
template<class TeamMemberType>
struct VectorSingleStruct {
const TeamMemberType& team_member;
KOKKOS_INLINE_FUNCTION
VectorSingleStruct(const TeamMemberType& team_member_):team_member(team_member_){}
};
} // namespace Impl
/** \brief Execution policy for parallel work over a threads within a team.
*
* The range is split over all threads in a team. The Mapping scheme depends on the architecture.
* This policy is used together with a parallel pattern as a nested layer within a kernel launched
* with the TeamPolicy. This variant expects a single count. So the range is (0,count].
*/
template<typename iType, class TeamMemberType>
KOKKOS_INLINE_FUNCTION
Impl::TeamThreadRangeBoundariesStruct<iType,TeamMemberType> TeamThreadRange(const TeamMemberType&, const iType& count);
/** \brief Execution policy for parallel work over a threads within a team.
*
* The range is split over all threads in a team. The Mapping scheme depends on the architecture.
* This policy is used together with a parallel pattern as a nested layer within a kernel launched
* with the TeamPolicy. This variant expects a begin and end. So the range is (begin,end].
*/
template<typename iType, class TeamMemberType>
KOKKOS_INLINE_FUNCTION
Impl::TeamThreadRangeBoundariesStruct<iType,TeamMemberType> TeamThreadRange(const TeamMemberType&, const iType& begin, const iType& end);
/** \brief Execution policy for a vector parallel loop.
*
* The range is split over all vector lanes in a thread. The Mapping scheme depends on the architecture.
* This policy is used together with a parallel pattern as a nested layer within a kernel launched
* with the TeamPolicy. This variant expects a single count. So the range is (0,count].
*/
template<typename iType, class TeamMemberType>
KOKKOS_INLINE_FUNCTION
Impl::ThreadVectorRangeBoundariesStruct<iType,TeamMemberType> ThreadVectorRange(const TeamMemberType&, const iType& count);
} // namespace Kokkos
#endif /* #define KOKKOS_EXECPOLICY_HPP */
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

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