rapidsmpf::communicator::MetadataPayloadExchange Class Reference

Interface for exchanging serialized metadata and payload between ranks. More...

#include <core.hpp>

Inheritance diagram for rapidsmpf::communicator::MetadataPayloadExchange:

Classes
class	Message
	Message class for communication. More...

Public Member Functions
virtual void	send (std::unique_ptr< Message > message)=0
	Send a single message to a remote rank. More...
virtual void	send (std::vector< std::unique_ptr< Message >> &&messages)=0
	Send messages to remote ranks. More...
virtual void	progress ()=0
	Progress the communication state machine. More...
virtual std::vector< std::unique_ptr< Message > >	recv ()=0
	Receive messages from remote ranks. More...
virtual void	finish ()=0
	Signal that no more messages will be sent. More...
virtual bool	is_idle () const =0
	Check if the communication layer is currently idle. More...

Detailed Description

Interface for exchanging serialized metadata and payload between ranks.

The MetadataPayloadExchange class defines an abstract interface for transmitting messages that contain both serialized metadata and a data payload. This abstraction simplifies scenarios where metadata and payload must be exchanged together as a single logical unit.

Concrete implementations, such as TagMetadataPayloadExchange, use the Communicator to implement this interface. In the future, other implementations may leverage specialized features beyond the basic Communicator API to further optimize this communication pattern.

Note

This class is not thread-safe. All methods must be called from the same thread.

All concrete implementations are expected to provide a constructor with the following signature:

DerivedMetadataPayloadExchange(
    std::shared_ptr<Communicator> comm,
    OpID op_id,
    std::function<std::unique_ptr<Buffer>(std::size_t)> allocate_buffer_fn,
    std::shared_ptr<Statistics> statistics
);

Definition at line 47 of file core.hpp.

Member Function Documentation

finish()

virtual void rapidsmpf::communicator::MetadataPayloadExchange::finish ( )

pure virtual

Signal that no more messages will be sent.

After calling this method, no further calls to send() are permitted. The implementation sends protocol-level termination markers to all peers so that each receiver knows the exact number of application messages to expect. This enables safe reuse of operation IDs: once all termination markers have been received and all expected messages processed, the communication layer considers itself idle and the tag/op_id can be reused.

Exceptions

std::logic_error

If called more than once.

Implemented in rapidsmpf::communicator::TagMetadataPayloadExchange.

is_idle()

virtual bool rapidsmpf::communicator::MetadataPayloadExchange::is_idle ( ) const

pure virtual

Check if the communication layer is currently idle.

Indicates whether there are any active or pending communication operations. Before finish() is called, a return value of true means no I/O operations are in progress. After finish() is called, true additionally requires that all peers have sent their termination markers and all expected messages have been received, meaning the op_id can safely be reused.

Returns

true if the communication layer is idle; false if activity is ongoing.

Implemented in rapidsmpf::communicator::TagMetadataPayloadExchange.

progress()

virtual void rapidsmpf::communicator::MetadataPayloadExchange::progress ( )

pure virtual

Progress the communication state machine.

Advances the internal state of the communication layer by processing pending operations such as receiving metadata, setting up data transfers, completing data transfers, and cleaning up completed operations. Completed messages are stored internally and can be retrieved via recv().

This method should be called periodically to make progress on communication.

Implemented in rapidsmpf::communicator::TagMetadataPayloadExchange.

recv()

virtual std::vector<std::unique_ptr<Message> > rapidsmpf::communicator::MetadataPayloadExchange::recv ( )

pure virtual

Receive messages from remote ranks.

The messages received by the calling process are guaranteed to be received in the same order as they were sent by the source remote rank. No ordering is guaranteed between messages received from different remote ranks.

Returns

Vector of completed messages ready for local processing.

Implemented in rapidsmpf::communicator::TagMetadataPayloadExchange.

send() [1/2]

virtual void rapidsmpf::communicator::MetadataPayloadExchange::send ( std::unique_ptr< Message >  message )

pure virtual

Send a single message to a remote rank.

Takes ownership of a ready message and manages its transmission, including metadata sending and coordination of data transfer.

The messages sent from the calling process to a destination remote rank are guaranteed to be received in the same order as they were sent. No ordering is guaranteed between messages sent to different remote ranks.

Parameters

message

Message ready to be sent to a remote rank.

Implemented in rapidsmpf::communicator::TagMetadataPayloadExchange.

send() [2/2]

virtual void rapidsmpf::communicator::MetadataPayloadExchange::send ( std::vector< std::unique_ptr< Message >> &&  messages )

pure virtual

Send messages to remote ranks.

Takes ownership of ready messages and manages their transmission, including metadata sending and coordination of data transfer.

The messages sent from the calling process to a destination remote rank are guaranteed to be received in the same order as they were sent. No ordering is guaranteed between messages sent to different remote ranks.

Parameters

messages

Vector of messages ready to be sent to remote ranks.

Implemented in rapidsmpf::communicator::TagMetadataPayloadExchange.

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The documentation for this class was generated from the following file:

• /__w/rapidsmpf/rapidsmpf/cpp/include/rapidsmpf/communicator/metadata_payload_exchange/core.hpp