stxxl::block_prefetcher< block_type, bid_iterator_type > Class Template Reference

Detailed Description

template<typename block_type, typename bid_iterator_type>
class stxxl::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.)

Definition at line 55 of file block_prefetcher.h.

Inheritance diagram for stxxl::block_prefetcher< block_type, bid_iterator_type >:

Collaboration diagram for stxxl::block_prefetcher< block_type, bid_iterator_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=default_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

Private Types
typedef block_type::bid_type	bid_type

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

Member Typedef Documentation

template<typename block_type , typename bid_iterator_type >

typedef block_type::bid_type stxxl::block_prefetcher< block_type, bid_iterator_type >::bid_type

private

Definition at line 57 of file block_prefetcher.h.

Constructor & Destructor Documentation

template<typename block_type , typename bid_iterator_type >

stxxl::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
do_after_fetch	unknown

Definition at line 103 of file block_prefetcher.h.

References STXXL_VERBOSE1.

template<typename block_type , typename bid_iterator_type >

stxxl::block_prefetcher< block_type, bid_iterator_type >::~block_prefetcher ( )

inline

Frees used memory.

Definition at line 209 of file block_prefetcher.h.

Member Function Documentation

template<typename block_type , typename bid_iterator_type >

bool stxxl::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

Definition at line 160 of file block_prefetcher.h.

References STXXL_VERBOSE1.

template<typename block_type , typename bid_iterator_type >

bool stxxl::block_prefetcher< block_type, bid_iterator_type >::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 197 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

unsigned_type stxxl::block_prefetcher< block_type, bid_iterator_type >::pos ( ) const

inline

Index of the next element in the consume sequence.

Definition at line 203 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

block_type* stxxl::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

Definition at line 150 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< sorted_runs_type, CompareType_, AllocStr_ >::initialize().

template<typename block_type , typename bid_iterator_type >

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

inlineprotected

Definition at line 80 of file block_prefetcher.h.

References STXXL_VERBOSE1.

Member Data Documentation

template<typename block_type , typename bid_iterator_type >

onoff_switch* stxxl::block_prefetcher< block_type, bid_iterator_type >::completed

protected

Definition at line 75 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

bid_iterator_type stxxl::block_prefetcher< block_type, bid_iterator_type >::consume_seq_begin

protected

Definition at line 60 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

bid_iterator_type stxxl::block_prefetcher< block_type, bid_iterator_type >::consume_seq_end

protected

Definition at line 61 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

completion_handler stxxl::block_prefetcher< block_type, bid_iterator_type >::do_after_fetch

protected

Definition at line 78 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

unsigned_type stxxl::block_prefetcher< block_type, bid_iterator_type >::nextconsume

protected

Definition at line 67 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

unsigned_type stxxl::block_prefetcher< block_type, bid_iterator_type >::nextread

protected

Definition at line 66 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

const int_type stxxl::block_prefetcher< block_type, bid_iterator_type >::nreadblocks

protected

Definition at line 69 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

int_type* stxxl::block_prefetcher< block_type, bid_iterator_type >::pref_buffer

protected

Definition at line 76 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

int_type* stxxl::block_prefetcher< block_type, bid_iterator_type >::prefetch_seq

protected

Definition at line 64 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

bid_type* stxxl::block_prefetcher< block_type, bid_iterator_type >::read_bids

protected

Definition at line 73 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

block_type* stxxl::block_prefetcher< block_type, bid_iterator_type >::read_buffers

protected

Definition at line 71 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

request_ptr* stxxl::block_prefetcher< block_type, bid_iterator_type >::read_reqs

protected

Definition at line 72 of file block_prefetcher.h.

template<typename block_type , typename bid_iterator_type >

unsigned_type stxxl::block_prefetcher< block_type, bid_iterator_type >::seq_length

protected

Definition at line 62 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