Buffer-Management
[Buffered Communication]

Collaboration diagram for Buffer-Management:

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Detailed Description

This section shows how the buffer used for buffered communication is managed.

Information about already allocated buffer-space is stored in the status-array.

But this information has no order which forces us everytime we want to allocate buffer-space to create an ordered list of already allocated buffer-space. To avoid this we have additionally an ordered linked-list. This list orders the indexes (== message-IDs) of the status-array-entries in ascending order of the memory-addresses. This enables fast searching for free buffer-space.

Allocated buffer-space is cleared by the receiving process by setting the appropriate flag in the status-array-entry. This is done by a DMA-Transfer and so no collaboration of the sending-process is needed. During the next allocation of buffer-space nodes with disabled buffer-flags are freed.

Data Structures
struct	moc_internal_buffer_node_struct
	Node of linked list holding information about allocated buffer-space. More...
Typedefs
typedef struct moc_internal_buffer_node_struct	moc_internal_buffer_node_t
	Node of linked list holding information about allocated buffer-space.
Functions
uint64_t	IMOC_bmalloc (uint32_t size, uint8_t mid)
	Allocate buffer-space.
moc_internal_buffer_node_t *	__attribute__ ((always_inline))
	void bmalloc_print_nodes() { if (!bmalloc_first_node) printf("No nodes in list\n"); else { int z = 0; moc_internal_buffer_node_t* t; for (t = bmalloc_first_node; t != 0; t = t->next_node) { printf( "Node %i: offset %u - size %u - valid %i - mid %u\n", z, node_handle.status_array_base[ t->mid ].buffer_offset, node_handle.status_array_base[ t->mid ].message_size, node_handle.status_array_base[ t->mid ].flags.bits.buffer_used, t->mid ); z++; } } }
Variables
moc_internal_buffer_node_t *	bmalloc_first_node = 0
	Pointer to first entry of linked-list.

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Typedef Documentation

typedef struct moc_internal_buffer_node_struct moc_internal_buffer_node_t

Node of linked list holding information about allocated buffer-space.

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Function Documentation

moc_internal_buffer_node_t* __attribute__

(

(always_inline)

)

void bmalloc_print_nodes() { if (!bmalloc_first_node) printf("No nodes in list\n"); else { int z = 0; moc_internal_buffer_node_t* t; for (t = bmalloc_first_node; t != 0; t = t->next_node) { printf( "Node %i: offset %u - size %u - valid %i - mid %u\n", z, node_handle.status_array_base[ t->mid ].buffer_offset, node_handle.status_array_base[ t->mid ].message_size, node_handle.status_array_base[ t->mid ].flags.bits.buffer_used, t->mid ); z++; } } }

Returns the next node holding valid buffer-information coming after node start.

During the search all invalid nodes the function stumbles across are freed and the links are corrected.

Parameters:

start

in start-node of search (NULL means beginning of list)

Returns:

next valid node

Definition at line 56 of file imoc_buffer_malloc.c.

References moc_message_status_struct::bits, moc_message_status_struct::flags, moc_internal_buffer_node_struct::mid, moc_internal_buffer_node_struct::next_node, node_handle, and moc_node_handle_ppu_struct::status_array_base.

Referenced by IMOC_get_data(), MOC_Barrier(), MOC_Bsend(), MOC_ISsend(), MOC_Recv(), and MOC_Ssend().

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uint64_t IMOC_bmalloc	(	uint32_t	size,
		uint8_t	mid
	)

Allocate buffer-space.

Parameters:

	size	in size of buffer-space
	mid	in corresponding message-ID

Returns:

effective address of allocated buffer-space (16-byte aligned)

Definition at line 85 of file imoc_buffer_malloc.c.

References moc_message_status_struct::bits, moc_node_handle_ppu_struct::buffer_base, moc_message_status_struct::buffer_offset, moc_node_handle_ppu_struct::buffer_size, moc_message_status_struct::flags, moc_message_status_struct::message_size, moc_internal_buffer_node_struct::mid, moc_internal_buffer_node_struct::next_node, node_handle, and moc_node_handle_ppu_struct::status_array_base.

Referenced by MOC_Bsend().

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Variable Documentation

moc_internal_buffer_node_t* bmalloc_first_node = 0

Pointer to first entry of linked-list.

Definition at line 20 of file imoc_buffer_malloc.c.

Referenced by MOC_Finalize().