Implements dynamically resizable prefetching pool. More...

#include <prefetch_pool.h>

Inheritance diagram for stxxl::prefetch_pool< BlockType >:

Collaboration diagram for stxxl::prefetch_pool< BlockType >:

Classes
struct	bid_hash
Public Types
typedef BlockType	block_type
typedef block_type::bid_type	bid_type
Public Member Functions
	prefetch_pool (unsigned_type init_size=1)
	Constructs pool.
void	swap (prefetch_pool &obj)
virtual	~prefetch_pool ()
	Waits for completion of all ongoing read requests and frees memory.
unsigned_type	size () const
	Returns number of owned blocks.
bool	hint (bid_type bid)
	Gives a hint for prefetching a block.
bool	hint (bid_type bid, write_pool< block_type > &w_pool)
bool	invalidate (bid_type bid)
bool	in_prefetching (bid_type bid)
request_ptr	read (block_type *&block, bid_type bid)
	Reads block. If this block is cached block is not read but passed from the cache.
request_ptr	read (block_type *&block, bid_type bid, write_pool< block_type > &w_pool)
unsigned_type	resize (unsigned_type new_size)
	Resizes size of the pool.
Protected Types
typedef std::pair< block_type *, request_ptr >	busy_entry
typedef compat_hash_map < bid_type, busy_entry, bid_hash >::result	hash_map_type
typedef std::list< block_type * > ::iterator	free_blocks_iterator
typedef hash_map_type::iterator	busy_blocks_iterator
Protected Attributes
std::list< block_type * >	free_blocks
hash_map_type	busy_blocks
unsigned_type	free_blocks_size

Detailed Description

template<class BlockType>
class stxxl::prefetch_pool< BlockType >

Implements dynamically resizable prefetching pool.

Examples:: mng/test_pool_pair.cpp, and mng/test_prefetch_pool.cpp.

Definition at line 34 of file prefetch_pool.h.

Member Typedef Documentation

template<class BlockType>

typedef block_type::bid_type stxxl::prefetch_pool< BlockType >::bid_type

Definition at line 38 of file prefetch_pool.h.

template<class BlockType>

typedef BlockType stxxl::prefetch_pool< BlockType >::block_type

Definition at line 37 of file prefetch_pool.h.

template<class BlockType>

typedef hash_map_type::iterator stxxl::prefetch_pool< BlockType >::busy_blocks_iterator [protected]

Definition at line 64 of file prefetch_pool.h.

template<class BlockType>

typedef std::pair<block_type *, request_ptr> stxxl::prefetch_pool< BlockType >::busy_entry [protected]

Definition at line 61 of file prefetch_pool.h.

template<class BlockType>

typedef std::list<block_type *>::iterator stxxl::prefetch_pool< BlockType >::free_blocks_iterator [protected]

Definition at line 63 of file prefetch_pool.h.

template<class BlockType>

typedef compat_hash_map<bid_type, busy_entry, bid_hash>::result stxxl::prefetch_pool< BlockType >::hash_map_type [protected]

Definition at line 62 of file prefetch_pool.h.

Constructor & Destructor Documentation

template<class BlockType>

stxxl::prefetch_pool< BlockType >::prefetch_pool ( unsigned_type init_size = 1 ) [inline, explicit]

Constructs pool.

Parameters:

init_size initial number of blocks in the pool

Definition at line 76 of file prefetch_pool.h.

template<class BlockType>

virtual stxxl::prefetch_pool< BlockType >::~prefetch_pool ( ) [inline, virtual]

Waits for completion of all ongoing read requests and frees memory.

Definition at line 91 of file prefetch_pool.h.

Member Function Documentation

template<class BlockType>

bool stxxl::prefetch_pool< BlockType >::hint ( bid_type bid ) [inline]

Gives a hint for prefetching a block.

Parameters:

bid	address of a block to be prefetched

Returns:: true if there was a free block to do prefetch and prefetching was scheduled, false otherwise

Note:: If there are no free blocks available (all blocks are already in reading or read but not retrieved by user calling read method) calling hint function has no effect

Definition at line 121 of file prefetch_pool.h.

Referenced by main().

template<class BlockType>

bool stxxl::prefetch_pool< BlockType >::hint	(	bid_type	bid,
		write_pool< block_type > &	w_pool
	)		`[inline]`

Definition at line 143 of file prefetch_pool.h.

References stxxl::write_pool< BlockType >::add(), and stxxl::write_pool< BlockType >::steal_request().

template<class BlockType>

bool stxxl::prefetch_pool< BlockType >::in_prefetching ( bid_type bid ) [inline]

Definition at line 192 of file prefetch_pool.h.

template<class BlockType>

bool stxxl::prefetch_pool< BlockType >::invalidate ( bid_type bid ) [inline]

Definition at line 174 of file prefetch_pool.h.

Referenced by main().

template<class BlockType>

request_ptr stxxl::prefetch_pool< BlockType >::read	(	block_type *&	block,
		bid_type	bid
	)		`[inline]`

Reads block. If this block is cached block is not read but passed from the cache.

Parameters:

block	block object, where data to be read to. If block was cached `block` 's ownership goes to the pool and block from cache is returned in `block` value.
bid	address of the block

Warning:: block parameter must be allocated dynamically using new .

Returns:: request pointer object of read operation

Definition at line 203 of file prefetch_pool.h.

Referenced by main().

template<class BlockType>

request_ptr stxxl::prefetch_pool< BlockType >::read	(	block_type *&	block,
		bid_type	bid,
		write_pool< block_type > &	w_pool
	)		`[inline]`

Definition at line 223 of file prefetch_pool.h.

References stxxl::write_pool< BlockType >::add(), and stxxl::write_pool< BlockType >::steal_request().

template<class BlockType>

unsigned_type stxxl::prefetch_pool< BlockType >::resize ( unsigned_type new_size ) [inline]

Resizes size of the pool.

Parameters:

new_size desired size of the pool. If some blocks are used for prefetching, these blocks can't be freed. Only free blocks (not in prefetching) can be freed by reducing the size of the pool calling this method.