block_prefetcher< BlockType, BidIteratorType > Class Template Reference

Detailed Description

template<typename BlockType, typename BidIteratorType>
class foxxll::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 56 of file block_prefetcher.hpp.

Collaboration diagram for block_prefetcher< BlockType, BidIteratorType >:

#include <block_prefetcher.hpp>

Public Types
using	bid_iterator_type = BidIteratorType
using	bid_type = typename block_type::bid_type
using	block_type = BlockType

Public Member Functions
	block_prefetcher (bid_iterator_type _cons_begin, bid_iterator_type _cons_end, size_t *_pref_seq, size_t _prefetch_buf_size, completion_handler do_after_fetch=completion_handler())
	block_prefetcher (const block_prefetcher &)=delete
	non-copyable: delete copy-constructor More...
	~block_prefetcher ()
	Frees used memory. More...
bool	block_consumed (block_type *&buffer)
bool	empty () const
block_prefetcher &	operator= (const block_prefetcher &)=delete
	non-copyable: delete assignment operator More...
size_t	pos () const
	Index of the next element in the consume sequence. More...
block_type *	pull_block ()

Protected Member Functions
block_type *	wait (size_t iblock)

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

Static Private Attributes
static constexpr bool	debug = false

Member Typedef Documentation

bid_iterator_type

using bid_iterator_type = BidIteratorType

Definition at line 62 of file block_prefetcher.hpp.

bid_type

using bid_type = typename block_type::bid_type

Definition at line 64 of file block_prefetcher.hpp.

block_type

using block_type = BlockType

Definition at line 61 of file block_prefetcher.hpp.

Constructor & Destructor Documentation

block_prefetcher() [1/2]

block_prefetcher ( bid_iterator_type  _cons_begin, bid_iterator_type  _cons_end, size_t *  _pref_seq, size_t  _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 110 of file block_prefetcher.hpp.

References set_switch_handler::set_switch_handler(), and TLX_LOG.

block_prefetcher() [2/2]

block_prefetcher ( const block_prefetcher< BlockType, BidIteratorType > &  )

delete

non-copyable: delete copy-constructor

~block_prefetcher()

~block_prefetcher ( )

inline

Frees used memory.

Definition at line 221 of file block_prefetcher.hpp.

Member Function Documentation

block_consumed()

bool 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 172 of file block_prefetcher.hpp.

References set_switch_handler::set_switch_handler(), and TLX_LOG.

Referenced by buf_istream< BlockType, BidIteratorType >::operator++(), buf_istream_reverse< BlockType, BidIteratorType >::operator++(), buf_istream< BlockType, BidIteratorType >::operator>>(), and buf_istream_reverse< BlockType, BidIteratorType >::operator>>().

empty()

bool 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 209 of file block_prefetcher.hpp.

operator=()

block_prefetcher& operator= ( const block_prefetcher< BlockType, BidIteratorType > &  )

delete

non-copyable: delete assignment operator

pos()

size_t pos ( ) const

inline

Index of the next element in the consume sequence.

Definition at line 215 of file block_prefetcher.hpp.

pull_block()

block_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 162 of file block_prefetcher.hpp.

References TLX_LOG.

Referenced by buf_istream< BlockType, BidIteratorType >::buf_istream().

wait()

block_type* wait ( size_t  iblock )

inlineprotected

Definition at line 87 of file block_prefetcher.hpp.

References TLX_LOG, onoff_switch::wait_for_on(), and stats::WAIT_OP_READ.

Member Data Documentation

completed

onoff_switch* completed

protected

Definition at line 82 of file block_prefetcher.hpp.

consume_seq_begin

bid_iterator_type consume_seq_begin

protected

Definition at line 67 of file block_prefetcher.hpp.

consume_seq_end

bid_iterator_type consume_seq_end

protected

Definition at line 68 of file block_prefetcher.hpp.

debug

constexpr bool debug = false

staticprivate

Definition at line 58 of file block_prefetcher.hpp.

do_after_fetch

completion_handler do_after_fetch

protected

Definition at line 85 of file block_prefetcher.hpp.

nextconsume

size_t nextconsume

protected

Definition at line 74 of file block_prefetcher.hpp.

nextread

size_t nextread

protected

Definition at line 73 of file block_prefetcher.hpp.

nreadblocks

const size_t nreadblocks

protected

Definition at line 76 of file block_prefetcher.hpp.

pref_buffer

size_t* pref_buffer

protected

Definition at line 83 of file block_prefetcher.hpp.

prefetch_seq

size_t* prefetch_seq

protected

Definition at line 71 of file block_prefetcher.hpp.

read_bids

bid_type* read_bids

protected

Definition at line 80 of file block_prefetcher.hpp.

read_buffers

block_type* read_buffers

protected

Definition at line 78 of file block_prefetcher.hpp.

read_reqs

request_ptr* read_reqs

protected

Definition at line 79 of file block_prefetcher.hpp.

seq_length

size_t seq_length

protected

Definition at line 69 of file block_prefetcher.hpp.

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

• extlib/foxxll/foxxll/mng/block_prefetcher.hpp