block_prefetcher< block_type, bid_iterator_type > Class Template Reference [Block scheduling sublayer]

Encapsulates asynchronous prefetching engine. More...

#include <block_prefetcher.h>

Collaboration diagram for block_prefetcher< block_type, bid_iterator_type >:

List of all members.

Public Member Functions
	block_prefetcher (bid_iterator_type _cons_begin, bid_iterator_type _cons_end, int_type *_pref_seq, int_type _prefetch_buf_size, completion_handler do_after_fetch=default_completion_handler())
	Constructs an object and immediately starts prefetching.
block_type *	pull_block ()
	Pulls next unconsumed block from the consumption sequence.
bool	block_consumed (block_type *&buffer)
	Exchanges buffers between prefetcher and application.
bool	empty () const
unsigned_type	pos () const
	~block_prefetcher ()
	Frees used memory.
Protected Member Functions
block_type *	wait (int_type iblock)
Protected Attributes
bid_iterator_type	consume_seq_begin
bid_iterator_type	consume_seq_end
unsigned_type	seq_length
int_type *	prefetch_seq
unsigned_type	nextread
unsigned_type	nextconsume
const int_type	nreadblocks
block_type *	read_buffers
request_ptr *	read_reqs
bid_type *	read_bids
onoff_switch *	completed
int_type *	pref_buffer
completion_handler	do_after_fetch

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Detailed Description

template<typename block_type, typename bid_iterator_type>
class block_prefetcher< block_type, bid_iterator_type >

Encapsulates asynchronous prefetching engine.

block_prefetcher overlaps I/Os with consumption of read data. Utilizes optimal asynchronous prefetch scheduling (by Peter Sanders et.al.)

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Constructor & Destructor Documentation

template<typename block_type , typename bid_iterator_type >

block_prefetcher< block_type, bid_iterator_type >::block_prefetcher	(	bid_iterator_type	_cons_begin,
		bid_iterator_type	_cons_end,
		int_type *	_pref_seq,
		int_type	_prefetch_buf_size,
		completion_handler	do_after_fetch = default_completion_handler()
	)			[inline]

Constructs an object and immediately starts prefetching.

Parameters:

	_cons_begin	bid_iterator pointing to the bid of the first block to be consumed
	_cons_end	bid_iterator pointing to the bid of the ( last + 1 ) block of consumption sequence
	_pref_seq	gives the prefetch order, is a pointer to the integer array that contains the indices of the blocks in the consumption sequence
	_prefetch_buf_size	amount of prefetch buffers to use

template<typename block_type , typename bid_iterator_type >

block_prefetcher< block_type, bid_iterator_type >::~block_prefetcher

(

)

[inline]

Frees used memory.

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Member Function Documentation

template<typename block_type , typename bid_iterator_type >

bool block_prefetcher< block_type, bid_iterator_type >::block_consumed

(

block_type *&

buffer

)

[inline]

Exchanges buffers between prefetcher and application.

Parameters:

buffer

pointer to the consumed buffer. After call if return value is true buffer contains valid pointer to the next unconsumed prefetched buffer.

Remarks:

parameter buffer must be value returned by pull_block() or block_consumed() methods

Returns:

false if there are no blocks to prefetch left, true if consumption sequence is not emptied

Referenced by buf_istream< BlkTp_, BIDIteratorTp_ >::operator++(), and buf_istream< BlkTp_, BIDIteratorTp_ >::operator>>().

template<typename block_type , typename bid_iterator_type >

block_type* block_prefetcher< block_type, bid_iterator_type >::pull_block

(

)

[inline]

Pulls next unconsumed block from the consumption sequence.

Returns:

Pointer to the already prefetched block from the internal buffer pool

Referenced by buf_istream< BlkTp_, BIDIteratorTp_ >::buf_istream().

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

• block_prefetcher.h