stxxl::block_prefetcher< BlockType, BidIteratorType > Class Template Reference

Detailed Description

template<typename BlockType, typename BidIteratorType>
class stxxl::block_prefetcher< BlockType, BidIteratorType >

Encapsulates asynchronous prefetching engine.

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

Definition at line 55 of file block_prefetcher.h.

Inheritance diagram for stxxl::block_prefetcher< BlockType, BidIteratorType >:

Collaboration diagram for stxxl::block_prefetcher< BlockType, BidIteratorType >:

Public Types
typedef BidIteratorType	bid_iterator_type
typedef block_type::bid_type	bid_type
typedef BlockType	block_type

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=completion_handler())
	Constructs an object and immediately starts prefetching. More...
	~block_prefetcher ()
	Frees used memory. More...
bool	block_consumed (block_type *&buffer)
	Exchanges buffers between prefetcher and application. More...
bool	empty () const
	No more consumable blocks available, but can't delete the prefetcher, because not all blocks may have been returned, yet. More...
unsigned_type	pos () const
	Index of the next element in the consume sequence. More...
block_type *	pull_block ()
	Pulls next unconsumed block from the consumption sequence. More...

Protected Member Functions
block_type *	wait (int_type iblock)

Protected Attributes
onoff_switch *	completed
bid_iterator_type	consume_seq_begin
bid_iterator_type	consume_seq_end
completion_handler	do_after_fetch
unsigned_type	nextconsume
unsigned_type	nextread
const int_type	nreadblocks
int_type *	pref_buffer
int_type *	prefetch_seq
bid_type *	read_bids
block_type *	read_buffers
request_ptr *	read_reqs
unsigned_type	seq_length

Additional Inherited Members
Private Member Functions inherited from stxxl::noncopyable
	noncopyable ()

Member Typedef Documentation

template<typename BlockType , typename BidIteratorType >

typedef BidIteratorType stxxl::block_prefetcher< BlockType, BidIteratorType >::bid_iterator_type

Definition at line 59 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

typedef block_type::bid_type stxxl::block_prefetcher< BlockType, BidIteratorType >::bid_type

Definition at line 61 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

typedef BlockType stxxl::block_prefetcher< BlockType, BidIteratorType >::block_type

Definition at line 58 of file block_prefetcher.h.

Constructor & Destructor Documentation

template<typename BlockType , typename BidIteratorType >

stxxl::block_prefetcher< BlockType, BidIteratorType >::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 = 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
do_after_fetch	unknown

Definition at line 107 of file block_prefetcher.h.

References STXXL_VERBOSE1.

template<typename BlockType , typename BidIteratorType >

stxxl::block_prefetcher< BlockType, BidIteratorType >::~block_prefetcher ( )

inline

Frees used memory.

Definition at line 211 of file block_prefetcher.h.

Member Function Documentation

template<typename BlockType , typename BidIteratorType >

bool stxxl::block_prefetcher< BlockType, BidIteratorType >::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

Definition at line 163 of file block_prefetcher.h.

References STXXL_VERBOSE1.

template<typename BlockType , typename BidIteratorType >

bool stxxl::block_prefetcher< BlockType, BidIteratorType >::empty ( ) const

inline

No more consumable blocks available, but can't delete the prefetcher, because not all blocks may have been returned, yet.

Definition at line 199 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

unsigned_type stxxl::block_prefetcher< BlockType, BidIteratorType >::pos ( ) const

inline

Index of the next element in the consume sequence.

Definition at line 205 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

block_type* stxxl::block_prefetcher< BlockType, BidIteratorType >::pull_block ( )

inline

Pulls next unconsumed block from the consumption sequence.

Returns

Pointer to the already prefetched block from the internal buffer pool

Definition at line 153 of file block_prefetcher.h.

References STXXL_VERBOSE1.

Referenced by stxxl::buf_istream_reverse< BlockType, BidIteratorType >::buf_istream_reverse(), and stxxl::stream::basic_runs_merger< typename runs_creator_type::sorted_runs_type, cmp_type, alloc_strategy_type >::initialize().

template<typename BlockType , typename BidIteratorType >

block_type* stxxl::block_prefetcher< BlockType, BidIteratorType >::wait ( int_type  iblock )

inlineprotected

Definition at line 84 of file block_prefetcher.h.

References STXXL_VERBOSE1.

Member Data Documentation

template<typename BlockType , typename BidIteratorType >

onoff_switch* stxxl::block_prefetcher< BlockType, BidIteratorType >::completed

protected

Definition at line 79 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

bid_iterator_type stxxl::block_prefetcher< BlockType, BidIteratorType >::consume_seq_begin

protected

Definition at line 64 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

bid_iterator_type stxxl::block_prefetcher< BlockType, BidIteratorType >::consume_seq_end

protected

Definition at line 65 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

completion_handler stxxl::block_prefetcher< BlockType, BidIteratorType >::do_after_fetch

protected

Definition at line 82 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

unsigned_type stxxl::block_prefetcher< BlockType, BidIteratorType >::nextconsume

protected

Definition at line 71 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

unsigned_type stxxl::block_prefetcher< BlockType, BidIteratorType >::nextread

protected

Definition at line 70 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

const int_type stxxl::block_prefetcher< BlockType, BidIteratorType >::nreadblocks

protected

Definition at line 73 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

int_type* stxxl::block_prefetcher< BlockType, BidIteratorType >::pref_buffer

protected

Definition at line 80 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

int_type* stxxl::block_prefetcher< BlockType, BidIteratorType >::prefetch_seq

protected

Definition at line 68 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

bid_type* stxxl::block_prefetcher< BlockType, BidIteratorType >::read_bids

protected

Definition at line 77 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

block_type* stxxl::block_prefetcher< BlockType, BidIteratorType >::read_buffers

protected

Definition at line 75 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

request_ptr* stxxl::block_prefetcher< BlockType, BidIteratorType >::read_reqs

protected

Definition at line 76 of file block_prefetcher.h.

template<typename BlockType , typename BidIteratorType >

unsigned_type stxxl::block_prefetcher< BlockType, BidIteratorType >::seq_length

protected

Definition at line 66 of file block_prefetcher.h.

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

• include/stxxl/bits/mng/block_prefetcher.h