xgboost::DMatrixCache< CacheT > Class Template Reference

Thread-aware FIFO cache for DMatrix related data. More...

#include <cache.h>

Data Structures
struct	Hash
struct	Item
struct	Key

Public Member Functions
	DMatrixCache (std::size_t cache_size)
DMatrixCache &	operator= (DMatrixCache &&that)
template<typename... Args>
std::shared_ptr< CacheT >	CacheItem (std::shared_ptr< DMatrix > m, Args const &... args)
	Cache a new DMatrix if it's not in the cache already.
template<typename... Args>
std::shared_ptr< CacheT >	ResetItem (std::shared_ptr< DMatrix > m, Args const &... args)
	Re-initialize the item in cache.
decltype(container_) const &	Container ()
	Get a const reference to the underlying hash map.
std::shared_ptr< CacheT >	Entry (DMatrix const *m) const

Static Public Member Functions
static constexpr std::size_t	DefaultSize ()

Protected Member Functions
void	CheckConsistent () const
void	ClearExpired ()
void	ClearExcess ()

Protected Attributes
std::unordered_map< Key, Item, Hash >	container_
std::queue< Key >	queue_
std::size_t	max_size_

Detailed Description

template<typename CacheT>
class xgboost::DMatrixCache< CacheT >

Thread-aware FIFO cache for DMatrix related data.

Template Parameters

CacheT

The type that needs to be cached.

Constructor & Destructor Documentation

DMatrixCache()

template<typename CacheT >

xgboost::DMatrixCache< CacheT >::DMatrixCache ( std::size_t  cache_size )

inlineexplicit

Parameters

cache_size

Maximum size of the cache.

Member Function Documentation

CacheItem()

template<typename CacheT >

template<typename... Args>

std::shared_ptr< CacheT > xgboost::DMatrixCache< CacheT >::CacheItem ( std::shared_ptr< DMatrix >  m, Args const &...  args  )

inline

Cache a new DMatrix if it's not in the cache already.

Passing in a shared_ptr is critical here. First to create a weak_ptr inside the entry this shared pointer is necessary. More importantly, the life time of this cache is tied to the shared pointer.

Parameters

m	shared pointer to the DMatrix that needs to be cached.
args	The arguments for constructing a new cache item, if needed.

Returns

The cache entry for passed in DMatrix, either an existing cache or newly created.

Container()

template<typename CacheT >

decltype(container_) const & xgboost::DMatrixCache< CacheT >::Container ( )

inline

Get a const reference to the underlying hash map.

Clear expired caches before returning.

ResetItem()

template<typename CacheT >

template<typename... Args>

std::shared_ptr< CacheT > xgboost::DMatrixCache< CacheT >::ResetItem ( std::shared_ptr< DMatrix >  m, Args const &...  args  )

inline

Re-initialize the item in cache.

Since the shared_ptr is used to hold the item, any reference that lives outside of the cache can no-longer be reached from the cache.

We use reset instead of erase to avoid walking through the whole cache for renewing a single item. (the cache is FIFO, needs to maintain the order).

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

• External/xgboost/include/xgboost/cache.h