MPISharedBuffer

#include <sbio/storage/mpi_shared.hh>

struct MPISharedBuffer

Defined in src/lib/sbio/storage/mpi_shared.hh:102

A buffer implementation backed by an MPI Shared Window.

This is used for roles like IndexRole that data processing ranks need to access concurrently.

The expectation is that the allocation of the memory for backing the Window be done by some controlling execution policy. This buffer then serves as a light view over it. It furthermore WILL be responsible for eventually cleaning up the memory; however, this is only done if there are no remaining references to the Window. It wraps the MPI_Win in an RC which manages the reference counting and performs destruction when the count reaches zero.

As there is the possibility for multiple StreamBrokers/other objects to run concurrently within a single rank, each of which using their own shared buffer, the MPISharedBuffer is tagged. The tag can be used for point-to-point communciation. Additionally, a sequence identifier is used to track the number of updates on this particular buffer. This helps prevent desynchronization by avoiding collectives called with the buffer from ranks moving at different rates.

List of all members

Name	Kind	Owner
`MPISharedBuffer`	`function`	Declared here
`MPISharedBuffer`	`function`	Declared here
`operator=`	`function`	Declared here
`MPISharedBuffer`	`function`	Declared here
`operator=`	`function`	Declared here
`ptr`	`function`	Declared here
`size`	`function`	Declared here
`window`	`function`	Declared here
`set_memory`	`function`	Declared here
`allocate`	`function`	Declared here
`tag`	`function`	Declared here
`set_tag`	`function`	Declared here
`seq`	`function`	Declared here
`set_seq`	`function`	Declared here
`fetch_next_seq`	`function`	Declared here
`is_dirty`	`function`	Declared here
`set_dirty`	`function`	Declared here
`memory_space`	`function`	Declared here
`m_ptr`	`variable`	Declared here
`m_size`	`variable`	Declared here
`m_window`	`variable`	Declared here
`m_tag`	`variable`	Declared here
`m_seq`	`variable`	Declared here

Public Methods

Return	Name	Description
	`MPISharedBuffer`	Defaulted constructor.
	`MPISharedBuffer` `inline`
`MPISharedBuffer &`	`operator=` `inline`	A shallow copy constructor.
	`MPISharedBuffer` `inline` `noexcept`	A shallow move constructor.
`MPISharedBuffer &`	`operator=` `inline` `noexcept`	A shallow move assignment.
`void *`	`ptr` `const` `inline`
`std::size_t`	`size` `const` `inline`
`const MPI_Win &`	`window` `const` `inline`
`void`	`set_memory` `inline`
`void`	`allocate` `inline`	Alternative interface for allocating an MPI_Win.
`int`	`tag` `const` `inline`
`void`	`set_tag` `inline`
`int`	`seq` `const` `inline`
`void`	`set_seq` `inline`
`int`	`fetch_next_seq` `inline`
`bool`	`is_dirty` `const` `inline`
`void`	`set_dirty` `inline`

MPISharedBuffer

MPISharedBuffer() = default

Defined in src/lib/sbio/storage/mpi_shared.hh:106

Defaulted constructor.

MPISharedBuffer

inline

inline MPISharedBuffer(const MPISharedBuffer & other)

Defined in src/lib/sbio/storage/mpi_shared.hh:108

operator=

inline

inline MPISharedBuffer & operator=(const MPISharedBuffer & other)

Defined in src/lib/sbio/storage/mpi_shared.hh:121

A shallow copy constructor.

If the Window is non-null at the time of move, then increment the reference count. The other MPISharedBuffer is NULL’d.

MPISharedBuffer

inline noexcept

inline MPISharedBuffer(MPISharedBuffer && other) noexcept

Defined in src/lib/sbio/storage/mpi_shared.hh:138

A shallow move constructor.

If the Window is non-null at the time of move, the reference count is not incremented as the other’s is moved and NULL’d.

operator=

inline noexcept

inline MPISharedBuffer & operator=(MPISharedBuffer && other) noexcept

Defined in src/lib/sbio/storage/mpi_shared.hh:155

A shallow move assignment.

If the Window is non-null at the time of move, the reference count is not incremented as the other’s is moved and NULL’d.

ptr

const inline

inline void * ptr() const

Defined in src/lib/sbio/storage/mpi_shared.hh:170

size

const inline

inline std::size_t size() const

Defined in src/lib/sbio/storage/mpi_shared.hh:173

window

const inline

inline const MPI_Win & window() const

Defined in src/lib/sbio/storage/mpi_shared.hh:174

set_memory

inline

inline void set_memory(void * ptr, std::size_t size)

Defined in src/lib/sbio/storage/mpi_shared.hh:176

allocate

inline

inline void allocate(MPI_Comm comm, std::size_t size)

Defined in src/lib/sbio/storage/mpi_shared.hh:190

Alternative interface for allocating an MPI_Win.

This alternative API, additional to the standard buffer concept, encapsulates creation of a fully managed RC<MPI_Win, MPIWinAllocator, MPIWinDeleter>.

Parameters

Parameter	Type	Description
`comm`	`MPI_Comm`	The communicator for creation of the shared MPI_Win.
`size`	`std::size_t`	The size of the shared buffer.

tag

const inline

inline int tag() const

Defined in src/lib/sbio/storage/mpi_shared.hh:203

set_tag

inline

inline void set_tag(int tag)

Defined in src/lib/sbio/storage/mpi_shared.hh:204

seq

const inline

inline int seq() const

Defined in src/lib/sbio/storage/mpi_shared.hh:206

set_seq

inline

inline void set_seq(int seq)

Defined in src/lib/sbio/storage/mpi_shared.hh:207

fetch_next_seq

inline

inline int fetch_next_seq()

Defined in src/lib/sbio/storage/mpi_shared.hh:208

is_dirty

const inline

inline bool is_dirty() const

Defined in src/lib/sbio/storage/mpi_shared.hh:210

set_dirty

inline

inline void set_dirty(bool)

Defined in src/lib/sbio/storage/mpi_shared.hh:211

Public Static Methods

Return	Name	Description
`constexpr MemorySpace`	`memory_space` `static` `inline` `constexpr`

memory_space

static inline constexpr

constexpr static inline constexpr MemorySpace memory_space()

Defined in src/lib/sbio/storage/mpi_shared.hh:104

Private Attributes

Return	Name	Description
`void *`	`m_ptr`	Pointer to the shared memory buffer.
`std::size_t`	`m_size`	Total size of the buffer/Window.
`RC< MPI_Win, MPIWinAllocator, MPIWinDeleter >`	`m_window`	Window over the shared memory buffer.
`int`	`m_tag`	Tag to allow point-to-point communication.
`int`	`m_seq`	A sequence number to track sync points.

m_ptr

void * m_ptr { nullptr }

Defined in src/lib/sbio/storage/mpi_shared.hh:214

Pointer to the shared memory buffer.

m_size

std::size_t m_size { 0 }

Defined in src/lib/sbio/storage/mpi_shared.hh:215

Total size of the buffer/Window.

m_window

RC< MPI_Win, MPIWinAllocator, MPIWinDeleter > m_window

Defined in src/lib/sbio/storage/mpi_shared.hh:216

Window over the shared memory buffer.

m_tag

int m_tag { -1 }

Defined in src/lib/sbio/storage/mpi_shared.hh:217

Tag to allow point-to-point communication.

m_seq

int m_seq { 0 }

Defined in src/lib/sbio/storage/mpi_shared.hh:218

A sequence number to track sync points.