Non-Blocking Communication
[Point-to-Point Communication]

Collaboration diagram for Non-Blocking Communication:

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Detailed Description

Non-blocking sending and receiving messages.

Because of restrictions of the Cell Broadband Engine non-blocking communication can only be provided with a lot of limitations. In fact the only operation where non-blocking communication make sense is synchronous send.

MOC_ISend uses blocking buffered send or non-blocking synchronous send according to the message size.

Note:

Every non-blocking communication operation has to be finished using MOC_Test or MOC_Wait, otherwise resources are no freed and some data are not copied correctly.

Data Structures
struct	moc_request_struct
	Communication-Request (Handle). More...
Typedefs
typedef struct moc_request_struct	MOC_Request
	Communication-Request (Handle).
Functions
int	MOC_ISend (void *buf, int count, MOC_Datatype datatype, int dest, int tag, MOC_Comm comm, MOC_Request *request)
	Performs a non-blocking standard mode send operation.
int	MOC_ISsend (void *buf, int count, MOC_Datatype datatype, int dest, int tag, MOC_Comm comm, MOC_Request *request)
	Performs a non-blocking synchronous mode send operation.
int	MOC_Test (MOC_Request *request, int *flag, MOC_Status *status)
	Tests, if a non-blocking communication has been completed.
int	MOC_Wait (MOC_Request *request, MOC_Status *status)
	Wait till a non-blocking communication has been completed.

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Typedef Documentation

typedef struct moc_request_struct MOC_Request

Communication-Request (Handle).

< Communication-Request (Handle)

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Function Documentation

int MOC_ISend	(	void *	buf,
		int	count,
		MOC_Datatype	datatype,
		int	dest,
		int	tag,
		MOC_Comm	comm,
		MOC_Request *	request
	)

Performs a non-blocking standard mode send operation.

Note:

This routine returns as soon as possible.

Parameters:

	buf	in Pointer to buffer where data is stored
	count	in Number of elements to be send (not equal to actual byte-value)
	datatype	in Type of elements to be send
	dest	in Rank of receiving process
	tag	in Tag of message
	comm	in communicator of message
	request	out communication request (handle)

Return values:

	MOC_SUCCESS	No error; MPI routine completed successfully.
	...	error-code

byte-count <= 4096 ==> buffered send

other ==> true non-blocking send

Definition at line 18 of file moc_isend.c.

References imoc_issend_request_struct::isFinished, moc_request_struct::issend_request, imoc_issend_request_struct::message_size, MOC_Bsend(), MOC_ISsend(), MOC_REQ_TYPE_ISSEND, MOC_SEND_TRESHOLD, node_handle, moc_node_handle_ppu_struct::rank, moc_request_struct::request_data, moc_request_struct::request_type, imoc_issend_request_struct::source, and imoc_issend_request_struct::tag.

Referenced by MOC_Bcast().

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int MOC_ISsend	(	void *	buf,
		int	count,
		MOC_Datatype	datatype,
		int	dest,
		int	tag,
		MOC_Comm	comm,
		MOC_Request *	request
	)

Performs a non-blocking synchronous mode send operation.

Note:

This routine returns as soon as possible (After the message-envelope has been written into the receiver's message-queue).

Parameters:

	buf	in Pointer to buffer where data is stored
	count	in Number of elements to be send (not equal to actual byte-value)
	datatype	in Type of elements to be send
	dest	in Rank of receiving process
	tag	in Tag of message
	comm	in communicator of message
	request	out communication request (handle)

Return values:

	MOC_SUCCESS	No error; MPI routine completed successfully.
	...	error-code

Definition at line 10 of file moc_issend_ppu.c.

References __attribute__(), moc_message_status_struct::bits, moc_message_status_struct::flags, IMOC_EA_REMOTE_QUEUE, IMOC_EA_REMOTE_QUEUE_ENTRY, IMOC_getFreeEntry(), IMOC_getFreeMID(), IMOC_LS_REMOTE_QUEUE, IMOC_MESSAGE_CHANNEL_DMA, IMOC_MESSAGE_CHANNEL_ENV, IMOC_TEST_ALIGNMENT, IMOC_TEST_BUFFER, IMOC_TEST_BYTECOUNT, IMOC_TEST_COMM_SEND, IMOC_TEST_PROC_NULL, IMOC_TEST_PROC_SELF, IMOC_TEST_RANK, IMOC_TEST_TAG_SEND, imoc_issend_request_struct::isFinished, moc_request_struct::issend_request, MEMCPY_GET_TRESHOLD, imoc_issend_request_struct::message_size, imoc_issend_request_struct::mid, MOC_ERR_INTERN, moc_ppu_thread_count, MOC_REQ_TYPE_ISSEND, moc_spu_thread_list, MOC_SUCCESS, node_handle, moc_node_handle_ppu_struct::queue_size, moc_node_handle_ppu_struct::rank, moc_request_struct::request_data, moc_request_struct::request_type, imoc_issend_request_struct::source, moc_node_handle_ppu_struct::status_array_base, and imoc_issend_request_struct::tag.

Referenced by MOC_ISend().

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int MOC_Test	(	MOC_Request *	request,
		int *	flag,
		MOC_Status *	status
	)

Tests, if a non-blocking communication has been completed.

Parameters:

	request	in Communication-Request (Handle)
	flag	out true, if communication-request has been completed
	status	out Object holding status-information

Return values:

	MOC_SUCCESS	No error; MPI routine completed successfully.
	...	error-code

Definition at line 13 of file moc_test.c.

References moc_message_status_struct::bits, moc_request_struct::dma_data, moc_message_status_struct::flags, IMOC_test_dma(), IMOC_testForMessageCompletion(), imoc_issend_request_struct::isFinished, moc_request_struct::issend_request, imoc_issend_request_struct::message_size, MOC_Status_struct::message_size, imoc_issend_request_struct::mid, MOC_ERR_REQUEST, MOC_Status_struct::MOC_ERROR, MOC_REQ_TYPE_DMA, MOC_REQ_TYPE_ISSEND, MOC_Status_struct::MOC_SOURCE, MOC_Status_struct::MOC_TAG, node_handle, moc_request_struct::request_data, moc_request_struct::request_type, imoc_dma_request_struct::size, imoc_issend_request_struct::source, moc_node_handle_ppu_struct::status_array_base, and imoc_issend_request_struct::tag.

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int MOC_Wait	(	MOC_Request *	request,
		MOC_Status *	status
	)

Wait till a non-blocking communication has been completed.

Parameters:

	request	in Communication-Request (Handle)
	status	out Object holding status-information

Return values:

	MOC_SUCCESS	No error; MPI routine completed successfully.
	...	error-code

Definition at line 11 of file moc_wait.c.

References moc_request_struct::dma_data, moc_message_status_struct::flags, IMOC_wait_dma(), IMOC_waitForMessageCompletion(), imoc_issend_request_struct::isFinished, moc_request_struct::issend_request, imoc_issend_request_struct::message_size, MOC_Status_struct::message_size, imoc_issend_request_struct::mid, MOC_ERR_REQUEST, MOC_Status_struct::MOC_ERROR, MOC_REQ_TYPE_DMA, MOC_REQ_TYPE_ISSEND, MOC_Status_struct::MOC_SOURCE, MOC_Status_struct::MOC_TAG, node_handle, moc_node_handle_ppu_struct::rank, moc_request_struct::request_data, moc_request_struct::request_type, imoc_dma_request_struct::size, imoc_issend_request_struct::source, moc_node_handle_ppu_struct::status_array_base, imoc_issend_request_struct::tag, and moc_message_status_struct::value.

Referenced by MOC_Bcast().

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