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Kokkos_Atomic_Exchange.hpp
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Kokkos_Atomic_Exchange.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
*/
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
#include <xmmintrin.h>
#endif
#include <Kokkos_Macros.hpp>
#if defined( KOKKOS_ATOMIC_HPP ) && ! defined( KOKKOS_ATOMIC_EXCHANGE_HPP )
#define KOKKOS_ATOMIC_EXCHANGE_HPP
namespace Kokkos {
//----------------------------------------------------------------------------
#if defined( KOKKOS_ENABLE_CUDA )
#if defined(__CUDA_ARCH__) || defined(KOKKOS_IMPL_CUDA_CLANG_WORKAROUND)
__inline__ __device__
int atomic_exchange( volatile int * const dest , const int val )
{
// return __iAtomicExch( (int*) dest , val );
return atomicExch( (int*) dest , val );
}
__inline__ __device__
unsigned int atomic_exchange( volatile unsigned int * const dest , const unsigned int val )
{
// return __uAtomicExch( (unsigned int*) dest , val );
return atomicExch( (unsigned int*) dest , val );
}
__inline__ __device__
unsigned long long int atomic_exchange( volatile unsigned long long int * const dest , const unsigned long long int val )
{
// return __ullAtomicExch( (unsigned long long*) dest , val );
return atomicExch( (unsigned long long*) dest , val );
}
/** \brief Atomic exchange for any type with compatible size */
template< typename T >
__inline__ __device__
T atomic_exchange(
volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) , const T & >::type val )
{
// int tmp = __ullAtomicExch( (int*) dest , *((int*)&val) );
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
int tmp = atomicExch( ((int*)dest) , *((int*)&val) );
return *((T*)&tmp);
}
template< typename T >
__inline__ __device__
T atomic_exchange(
volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
sizeof(T) == sizeof(unsigned long long int) , const T & >::type val )
{
typedef unsigned long long int type ;
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
// type tmp = __ullAtomicExch( (type*) dest , *((type*)&val) );
type tmp = atomicExch( ((type*)dest) , *((type*)&val) );
return *((T*)&tmp);
}
template < typename T >
__inline__ __device__
T atomic_exchange( volatile T * const dest ,
typename Kokkos::Impl::enable_if<
( sizeof(T) != 4 )
&& ( sizeof(T) != 8 )
, const T >::type& val )
{
T return_val;
// This is a way to (hopefully) avoid dead lock in a warp
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
int done = 0;
unsigned int active = __ballot(1);
unsigned int done_active = 0;
while (active!=done_active) {
if(!done) {
if( Impl::lock_address_cuda_space( (void*) dest ) ) {
return_val = *dest;
*dest = val;
Impl::unlock_address_cuda_space( (void*) dest );
done = 1;
}
}
done_active = __ballot(done);
}
return return_val;
}
/** \brief Atomic exchange for any type with compatible size */
template< typename T >
__inline__ __device__
void atomic_assign(
volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) , const T & >::type val )
{
// (void) __ullAtomicExch( (int*) dest , *((int*)&val) );
(void) atomicExch( ((int*)dest) , *((int*)&val) );
}
template< typename T >
__inline__ __device__
void atomic_assign(
volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
sizeof(T) == sizeof(unsigned long long int) , const T & >::type val )
{
typedef unsigned long long int type ;
// (void) __ullAtomicExch( (type*) dest , *((type*)&val) );
(void) atomicExch( ((type*)dest) , *((type*)&val) );
}
template< typename T >
__inline__ __device__
void atomic_assign(
volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
sizeof(T) != sizeof(unsigned long long int)
, const T & >::type val )
{
(void) atomic_exchange(dest,val);
}
#endif
#endif
//----------------------------------------------------------------------------
#if !defined(__CUDA_ARCH__) || defined(KOKKOS_IMPL_CUDA_CLANG_WORKAROUND)
#if defined(KOKKOS_ENABLE_GNU_ATOMICS) || defined(KOKKOS_ENABLE_INTEL_ATOMICS)
template< typename T >
inline
T atomic_exchange( volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) || sizeof(T) == sizeof(long)
, const T & >::type val )
{
typedef typename Kokkos::Impl::if_c< sizeof(T) == sizeof(int) , int , long >::type type ;
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
const type v = *((type*)&val); // Extract to be sure the value doesn't change
type assumed ;
union U {
T val_T ;
type val_type ;
inline U() {};
} old ;
old.val_T = *dest ;
do {
assumed = old.val_type ;
old.val_type = __sync_val_compare_and_swap( (volatile type *) dest , assumed , v );
} while ( assumed != old.val_type );
return old.val_T ;
}
#if defined(KOKKOS_ENABLE_ASM) && defined ( KOKKOS_ENABLE_ISA_X86_64 )
template< typename T >
inline
T atomic_exchange( volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(Impl::cas128_t)
, const T & >::type val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
union U {
Impl::cas128_t i ;
T t ;
inline U() {};
} assume , oldval , newval ;
oldval.t = *dest ;
newval.t = val;
do {
assume.i = oldval.i ;
oldval.i = Impl::cas128( (volatile Impl::cas128_t*) dest , assume.i , newval.i );
} while ( assume.i != oldval.i );
return oldval.t ;
}
#endif
//----------------------------------------------------------------------------
template < typename T >
inline
T atomic_exchange( volatile T * const dest ,
typename Kokkos::Impl::enable_if<
( sizeof(T) != 4 )
&& ( sizeof(T) != 8 )
#if defined(KOKKOS_ENABLE_ASM) && defined ( KOKKOS_ENABLE_ISA_X86_64 )
&& ( sizeof(T) != 16 )
#endif
, const T >::type& val )
{
while( !Impl::lock_address_host_space( (void*) dest ) );
T return_val = *dest;
// Don't use the following line of code here:
//
//const T tmp = *dest = val;
//
// Instead, put each assignment in its own statement. This is
// because the overload of T::operator= for volatile *this should
// return void, not volatile T&. See Kokkos #177:
//
// https://github.com/kokkos/kokkos/issues/177
*dest = val;
const T tmp = *dest;
#ifndef KOKKOS_COMPILER_CLANG
(void) tmp;
#endif
Impl::unlock_address_host_space( (void*) dest );
return return_val;
}
template< typename T >
inline
void atomic_assign( volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) || sizeof(T) == sizeof(long)
, const T & >::type val )
{
typedef typename Kokkos::Impl::if_c< sizeof(T) == sizeof(int) , int , long >::type type ;
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
const type v = *((type*)&val); // Extract to be sure the value doesn't change
type assumed ;
union U {
T val_T ;
type val_type ;
inline U() {};
} old ;
old.val_T = *dest ;
do {
assumed = old.val_type ;
old.val_type = __sync_val_compare_and_swap( (volatile type *) dest , assumed , v );
} while ( assumed != old.val_type );
}
#if defined( KOKKOS_ENABLE_ASM ) && defined ( KOKKOS_ENABLE_ISA_X86_64 )
template< typename T >
inline
void atomic_assign( volatile T * const dest ,
typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(Impl::cas128_t)
, const T & >::type val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
_mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
union U {
Impl::cas128_t i ;
T t ;
inline U() {};
} assume , oldval , newval ;
oldval.t = *dest ;
newval.t = val;
do {
assume.i = oldval.i ;
oldval.i = Impl::cas128( (volatile Impl::cas128_t*) dest , assume.i , newval.i);
} while ( assume.i != oldval.i );
}
#endif
template < typename T >
inline
void atomic_assign( volatile T * const dest ,
typename Kokkos::Impl::enable_if<
( sizeof(T) != 4 )
&& ( sizeof(T) != 8 )
#if defined(KOKKOS_ENABLE_ASM) && defined ( KOKKOS_ENABLE_ISA_X86_64 )
&& ( sizeof(T) != 16 )
#endif
, const T >::type& val )
{
while( !Impl::lock_address_host_space( (void*) dest ) );
// This is likely an aggregate type with a defined
// 'volatile T & operator = ( const T & ) volatile'
// member. The volatile return value implicitly defines a
// dereference that some compilers (gcc 4.7.2) warn is being ignored.
// Suppress warning by casting return to void.
//(void)( *dest = val );
*dest = val;
Impl::unlock_address_host_space( (void*) dest );
}
//----------------------------------------------------------------------------
#elif defined( KOKKOS_ENABLE_OPENMP_ATOMICS )
template < typename T >
inline
T atomic_exchange( volatile T * const dest , const T val )
{
T retval;
//#pragma omp atomic capture
#pragma omp critical
{
retval = dest[0];
dest[0] = val;
}
return retval;
}
template < typename T >
inline
void atomic_assign( volatile T * const dest , const T val )
{
//#pragma omp atomic
#pragma omp critical
{
dest[0] = val;
}
}
#endif
#endif
} // namespace Kokkos
#endif

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