Memory

Overview

Each AIE core has access to up to 4 Data Memories (DM). Global variables, graph communication buffers (such as windows), and the stack are placed by the linker on these memories.

The AIE API provides a number of functions and types that allow applications to efficiently read and write vector data stored on DM.

Vector alignment

Applications can load from DM into vector registers and store the contents of vector registers into DM. Memory instructions in the AIE that operate on vectors have alignment requirements. Therefore, functions are provided for both aligned and unaligned accesses. Aligned accesses are done using theaie::load_vandaie::store_vfunctions, while unaligned accesses are performed usingaie::load_unaligned_vandaie::store_unaligned_vfunctions. Unaligned accesses may incur additional overhead depending on the amount of misalignment.

Users can ensure that buffers are aligned using standard C/C++ facilities such as alignas. The API provides a global constant value (aie::vector_decl_align) that can be used to align the buffer to a boundary that works for any vector size.

      alignas(aie::vector_decl_align)
      static
      int16my_buffer[BUFFER_COUNT];
     

Memory bank conflicts

AIE cores are able to perform several vector load/store operations per instruction. However, in order for them to be executed in parallel, they must target different memory banks. aiecompiler will try to evenly distribute buffers from communication primitives, and users can manually place buffers on specific banks by specifying the address range in the linker script file.

In general the compiler will try to schedule many accesses in the same instruction when possible. However, in scenarios in which this would translate into bank conflicts, this behavior might not be desirable. The compiler provides type annotations to associate memory accesses to virtual resources. Accesses using types that are associated to the same virtual resource will not be scheduled in the same instruction.

      voidfn(
      int
      __aie_dm_resource_a* A,
     

      int* B,
     

      int
      __aie_dm_resource_a* C)
     

      {
     

      aie::vectorv1 = aie::load_v<8>(A);
      // Access from A and C are bound to the same virtual resource so they
     

      aie::vectorv2 = aie::load_v<8>(B);
      // are never scheduled on the same instruction. B is not annotated so
     

      aie::vectorv3 = aie::load_v<8>(C);
      // its memory accesses can be scheduled in the same instruction with
     

      // accesses to A or C.
     

      ...
     

      }
     

Also, most memory access functions in the AIE API accept an enum value fromaie_dm_resourcethat can be used to bind individual accesses to a virtual resource.

      voidfn(
      int
      __aie_dm_resource_a* A,
     

      int* B
     

      {
     

      aie::vectorv1 = aie::load_v<8>(A);
     

      aie::vectorv2 = aie::load_v<8>(B);
      // This access can be scheduled on the same instruction as the access
     

      // to A since B is not annotated.
     

      aie::vectorv3 = aie::load_v<8, aie_dm_resource::a>(B);
      // This specific access to B is annotated with
     

      // the same virtual resource as A, so they cannot
     

      // be scheduled on the same instruction.
     

      ...
     

      }
     

Typedefs
templateaie_dm_resourceResource = aie_dm_resource::none>
using	aie::circular_iterator=detail::circular_iterator< T, Elems, 1, Resource >
	More...
templateaie_dm_resourceResource = aie_dm_resource::none>
using	aie::const_circular_iterator=detail::const_circular_iterator< T, Elems, 1, Resource >
	More...
template
using	aie::const_random_circular_iterator=detail::const_random_circular_iterator< T, Elems, 1 >
	More...
template
using	aie::random_circular_iterator=detail::random_circular_iterator< T, Elems, 1 >
	More...

Functions
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexpr auto	aie::begin_circular(T *base)
	More...
template<aie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexpr auto	aie::begin_circular(T *base, size_t n)
	More...
template<aie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t Elems = 0>
constexpr auto	aie::begin_circular(T(&base)[Elems])
	More...
template
constexpr auto	aie::begin_random_circular(T *base)
	More...
template
constexpr auto	aie::begin_random_circular(T *base, size_t n)
	More...
template
constexpr auto	aie::begin_random_circular(T(&base)[Elems])
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
constexpr auto	aie::begin_restrict_vector(const T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
constexpr auto	aie::begin_restrict_vector(T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
constexpr auto	aie::begin_vector(const T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
constexpr auto	aie::begin_vector(T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexpr auto	aie::begin_vector_circular(T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexpr auto	aie::begin_vector_circular(T *base, size_t n)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t ArrayElems = 0>
constexpr auto	aie::begin_vector_circular(T(&base)[ArrayElems])
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexprconst_circular_iterator< T, Elems, Resource >	aie::cbegin_circular(const T *base)
	More...
template<aie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexprconst_circular_iterator< T, dynamic_extent, Resource >	aie::cbegin_circular(const T *base, size_t n)
	More...
template<aie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t Elems = 0>
constexprconst_circular_iterator< T, Elems, Resource >	aie::cbegin_circular(const T(&base)[Elems])
	More...
template
constexpr auto	aie::cbegin_random_circular(const T *base)
	More...
template
constexpr auto	aie::cbegin_random_circular(const T *base, size_t n)
	More...
template
constexpr auto	aie::cbegin_random_circular(const T(&base)[Elems])
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
constexpr auto	aie::cbegin_restrict_vector(const T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
constexpr auto	aie::cbegin_vector(const T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexpr auto	aie::cbegin_vector_circular(const T *base)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>
constexpr auto	aie::cbegin_vector_circular(const T *base, size_t n)
	More...
templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t ArrayElems = 0>
constexpr auto	aie::cbegin_vector_circular(const T(&base)[ArrayElems])
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
auto	aie::load_floor_bytes_v(const T *ptr, size_t bytes) ->vector<aie_dm_resource_remove_t< T >, Elems >
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
auto	aie::load_floor_v(const T *ptr, unsigned n=Elems) ->vector<aie_dm_resource_remove_t< T >, Elems >
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
auto	aie::load_unaligned_v(const T *ptr, unsigned aligned_elems=1) ->vector<aie_dm_resource_remove_t< T >, Elems >
	More...
template<aie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
auto	aie::load_unaligned_v(const T *ptr, unsigned aligned_elems=1) ->vector<aie_dm_resource_remove_t< T >, native_vector_length_v< T >>
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
auto	aie::load_v(const T *ptr) ->vector<aie_dm_resource_remove_t< T >, Elems >
	More...
template<aie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT = void>
auto	aie::load_v(const T *ptr) ->vector<aie_dm_resource_remove_t< T >, native_vector_length_v< T >>
	More...
templateaie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT1 = void,ElemBaseTypeT2 = void>
T1 *	aie::store_unaligned_v(T1 *ptr, constvector< T2, Elems > &v, unsigned aligned_elems=1)
	More...
template<aie_dm_resourceResource = aie_dm_resource::none,DecoratedElemBaseTypeT1 = void,ElemBaseTypeT2, unsigned Elems = 0>
T1 *	aie::store_v(T1 *ptr, constvector< T2, Elems > &v)
	More...

Typedef Documentation

circular_iterator

templateaie_dm_resourceResource = aie_dm_resource::none>

usingaie::circular_iterator= typedefdetail::circular_iterator

Implements an iterator that wraps around when it reaches the end of the buffer and, thus, has no end.

The interface meetsforward iterator.

Template Parameters

T	Type of the elements in the array.
Elems	Size of the array if it is different than dynamic_extent. Otherwise, the size is not known at compile time.

const_circular_iterator

templateaie_dm_resourceResource = aie_dm_resource::none>

usingaie::const_circular_iterator= typedefdetail::const_circular_iterator

Same ascircular_iterator, but the contents of the iterated array cannot be modified.

const_random_circular_iterator

template

usingaie::const_random_circular_iterator= typedefdetail::const_random_circular_iterator

Same asrandom_circular_iterator, but the contents of the iterated array cannot be modified.

random_circular_iterator

template

usingaie::random_circular_iterator= typedefdetail::random_circular_iterator

Implements an iterator that wraps around when it reaches the end or the beginning of the buffer and, thus, has no end.

The interface meetsrandom access iterator.

Template Parameters

T	Type of the elements in the array.
Elems	Size of the array if it is different than dynamic_extent. Otherwise, the size is not known at compile time.

Function Documentation

begin_circular()[1/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexpr auto aie::begin_circular ( T * base )

constexpr

Returns a circular iterator for the array described by the given address and size.

Template Parameters

Elems

Number of elements in the array.

Parameters

base	Starting address for the iterator.

begin_circular()[2/3]

template< aie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexpr auto aie::begin_circular ( T * base, size_t n )

constexpr

Returns a circular iterator for the array described by the given address and size.

Parameters

base	Starting address for the iterator.
n	Number of elements in the array.

begin_circular()[3/3]

template< aie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t Elems = 0>

constexpr auto aie::begin_circular ( T(&) base[Elems] )

constexpr

Returns a circular iterator for the array described by the given address and size.

Parameters

base	Statically-sized array.

begin_random_circular()[1/3]

template

constexpr auto aie::begin_random_circular ( T * base )

constexpr

Returns a random-access circular iterator for the array described by the given address and size.

Template Parameters

Elems

Number of elements in the array.

Parameters

base	Starting address for the iterator.

begin_random_circular()[2/3]

template

constexpr auto aie::begin_random_circular ( T * base, size_t n )

constexpr

Returns a random-access circular iterator for the array described by the given address and size.

Parameters

base	Starting address for the iterator.
n	Number of elements in the array.

begin_random_circular()[3/3]

template

constexpr auto aie::begin_random_circular ( T(&) base[Elems] )

constexpr

Returns a random-access circular iterator for the array described by the given address and size.

Parameters

base	Statically-sized array.

begin_restrict_vector()[1/2]

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

constexpr auto aie::begin_restrict_vector ( const T * base )

constexpr

Same as begin_vector, but the given pointer is considered restrict.

The returned pointer is const.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.

begin_restrict_vector()[2/2]

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

constexpr auto aie::begin_restrict_vector ( T * base )

constexpr

Same as begin_vector, but the given pointer is considered restrict.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.

begin_vector()[1/2]

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

constexpr auto aie::begin_vector ( const T * base )

constexpr

Returns a vector iterator starting at the given address. Elements in the vector will have the same type of the pointer parameter, and the size of the vector is specified via a template argument. The pointer is assumed to meet the alignment requirements for a vector load of this size.

The returned pointer is const.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.

begin_vector()[2/2]

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

constexpr auto aie::begin_vector ( T * base )

constexpr

Returns a vector iterator starting at the given address. Elements in the vector will have the same type of the pointer parameter, and the size of the vector is specified via a template argument. The pointer is assumed to meet the alignment requirements for a vector load of this size.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.

begin_vector_circular()[1/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexpr auto aie::begin_vector_circular ( T * base )

constexpr

Returns a circular iterator for the array described by the given address and size.

Template Parameters

Elems	Number of elements in the vectors returned by the iterator.
ArrayElems	Number of elements in the array.

Parameters

base	Starting address for the iterator.

begin_vector_circular()[2/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexpr auto aie::begin_vector_circular ( T * base, size_t n )

constexpr

Returns a circular iterator for the array described by the given address and size.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.
n	Number of elements in the array.

begin_vector_circular()[3/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t ArrayElems = 0>

constexpr auto aie::begin_vector_circular ( T(&) base[ArrayElems] )

constexpr

Returns a circular iterator for the array described by the given address and size.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Statically-sized array.

cbegin_circular()[1/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexprconst_circular_iterator aie::cbegin_circular ( const T * base )

constexpr

Similar to begin_circular, but the returned iterator is constant.

Template Parameters

Elems

Number of elements in the array.

Parameters

base	Starting address for the iterator.

cbegin_circular()[2/3]

template< aie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexprconst_circular_iterator aie::cbegin_circular ( const T * base, size_t n )

constexpr

Similar to begin_circular, but the returned iterator is constant.

Parameters

base	Starting address for the iterator.
n	Number of elements in the array.

cbegin_circular()[3/3]

template< aie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t Elems = 0>

constexprconst_circular_iterator aie::cbegin_circular ( const T(&) base[Elems] )

constexpr

Similar to begin_circular, but the returned iterator is constant.

Parameters

base	Statically-sized array.

cbegin_random_circular()[1/3]

template

constexpr auto aie::cbegin_random_circular ( const T * base )

constexpr

Similar to begin_random_circular, but the returned iterator is constant.

Template Parameters

Elems

Number of elements in the array.

Parameters

base	Starting address for the iterator.

cbegin_random_circular()[2/3]

template

constexpr auto aie::cbegin_random_circular ( const T * base, size_t n )

constexpr

Similar to begin_random_circular, but the returned iterator is constant.

Parameters

base	Starting address for the iterator.
n	Number of elements in the array.

cbegin_random_circular()[3/3]

template

constexpr auto aie::cbegin_random_circular ( const T(&) base[Elems] )

constexpr

Similar to begin_random_circular, but the returned iterator is constant.

Parameters

base	Statically-sized array.

cbegin_restrict_vector()

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

constexpr auto aie::cbegin_restrict_vector ( const T * base )

constexpr

Same as begin_vector, but the given pointer is considered restrict.

The returned pointer is const.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.

cbegin_vector()

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

constexpr auto aie::cbegin_vector ( const T * base )

constexpr

Same as begin_vector.

The returned pointer is const.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.

cbegin_vector_circular()[1/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexpr auto aie::cbegin_vector_circular ( const T * base )

constexpr

Similar to begin_circular, but the returned iterator is constant.

Template Parameters

Elems	Number of elements in the vectors returned by the iterator.
ArrayElems	Number of elements in the array.

Parameters

base	Starting address for the iterator.

cbegin_vector_circular()[2/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void>

constexpr auto aie::cbegin_vector_circular ( const T * base, size_t n )

constexpr

Similar to begin_circular, but the returned iterator is constant.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Starting address for the iterator.
n	Number of elements in the array.

cbegin_vector_circular()[3/3]

templateaie_dm_resourceResource = aie_dm_resource::none, typename T = void, size_t ArrayElems = 0>

constexpr auto aie::cbegin_vector_circular ( const T(&) base[ArrayElems] )

constexpr

Similar to begin_circular, but the returned iterator is constant.

Template Parameters

Elems

Number of elements in the vectors returned by the iterator.

Parameters

base	Statically-sized array.

load_floor_bytes_v()

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

auto aie::load_floor_bytes_v	(	const T *	ptr,
		size_t	bytes
	)		->vector<aie_dm_resource_remove_t, Elems>

Load a vector of Elems size whose elements have type T. The pointer will be aligned to bytes.

Template Parameters

Elems

Size of the vector to be read from memory

Parameters

ptr	Address data is read from
n	Numbers of bytes to which the input pointer is aligned. Must be a power of two.

load_floor_v()

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

auto aie::load_floor_v	(	const T *	ptr,
		unsigned	n=Elems
	)		->vector<aie_dm_resource_remove_t, Elems>

Load a vector of Elems size whose elements have type T. The pointer will be aligned to n * sizeof(T).

Template Parameters

Elems

Size of the vector to be read from memory

Parameters

ptr	Address data is read from
n	Numbers of elements of type T to which the input pointer is aligned. Must be a power of two.

load_unaligned_v()[1/2]

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

auto aie::load_unaligned_v	(	const T *	ptr,
		unsigned	aligned_elems=1
	)		->vector<aie_dm_resource_remove_t, Elems>

Load a vector of Elems size whose elements have type T. The pointer is assumed to be aligned to T.

        for(
        unsignedi = 0; i < Elems; ++i)
       

        out[i] = ptr[i];
       

Template Parameters

Elems

Size of the vector to be read from memory

Parameters

ptr	Address data is read from
aligned_elems	Number of elements the pointer is aligned to. If unspecified, the default value is 1.

load_unaligned_v()[2/2]

template< aie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

auto aie::load_unaligned_v	(	const T *	ptr,
		unsigned	aligned_elems=1
	)		->vector<aie_dm_resource_remove_t, native_vector_length_v>

Load a vector whose elements have type T. The size is automatically chosen with the optimal size for the current architecture. The pointer is assumed to be aligned to T.

        for(
        unsignedi = 0; i < Elems; ++i)
       

        out[i] = ptr[i];
       

Parameters

ptr	Address data is read from
aligned_elems	Number of elements the pointer is aligned to. If unspecified, the default value is 1.

load_v()[1/2]

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

auto aie::load_v

(

const T *

ptr

)

->vector<aie_dm_resource_remove_t, Elems>

Load a vector of Elems size whose elements have type T. The pointer is assumed to meet the alignment requirements for a vector load of this size.

        for(
        unsignedi = 0; i < Elems; ++i)
       

        out[i] = ptr[i];
       

Template Parameters

Elems

Size of the vector to be read from memory

Parameters

ptr	Address data is read from

load_v()[2/2]

template< aie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT = void>

auto aie::load_v

(

const T *

ptr

)

->vector<aie_dm_resource_remove_t, native_vector_length_v>

Load a vector whose elements have type T. The size is automatically chosen with the optimal size for the current architecture. The pointer is assumed to meet the alignment requirements for a vector load of this size.

        for(
        unsignedi = 0; i < Elems; ++i)
       

        out[i] = ptr[i];
       

Parameters

ptr	Address data is read from

store_unaligned_v()

templateaie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT1 = void, ElemBaseTypeT2 = void>

T1* aie::store_unaligned_v	(	T1 *	ptr,
		constvector< T2, Elems > &	v,
		unsigned	aligned_elems=1
	)

Store a vector of Elems size whose elements have type T. The pointer is assumed to be aligned to T.

        for(
        unsignedi = 0; i < Elems; ++i)
       

        ptr[i] = v[i];
       

Parameters

ptr	Address data is written to
v	Vectorto be written to memory
aligned_elems	Number of elements the pointer is aligned to. If unspecified, the default value is 1.

store_v()

template< aie_dm_resourceResource = aie_dm_resource::none, DecoratedElemBaseTypeT1 = void, ElemBaseTypeT2, unsigned Elems = 0>

T1* aie::store_v	(	T1 *	ptr,
		constvector< T2, Elems > &	v
	)

Store a vector of Elems size whose elements have type T. The pointer is assumed to meet the alignment requirements for a vector store of this size.

        for(
        unsignedi = 0; i < Elems; ++i)
       

        ptr[i] = v[i];
       

Parameters

ptr	Address data is written to
v	Vectorto be written to memory