Inherits AZ::IO::StreamStackEntry.

Classes
struct	Section

Public Member Functions
	BlockCache (u64 cacheSize, u32 blockSize, u32 alignment, bool onlyEpilogWrites)

	BlockCache (BlockCache &&rhs)=delete

	BlockCache (const BlockCache &rhs)=delete

BlockCache &	operator= (BlockCache &&rhs)=delete

BlockCache &	operator= (const BlockCache &rhs)=delete

void	QueueRequest (FileRequest *request) override

bool	ExecuteRequests () override

void	UpdateStatus (Status &status) const override
	Gets a combined status update from all the nodes in the stack.

void	UpdateCompletionEstimates (AZStd::chrono::steady_clock::time_point now, AZStd::vector< FileRequest * > &internalPending, StreamerContext::PreparedQueue::iterator pendingBegin, StreamerContext::PreparedQueue::iterator pendingEnd) override

void	AddDelayedRequests (AZStd::vector< FileRequest * > &internalPending)

void	UpdatePendingRequestEstimations ()

void	FlushCache (const RequestPath &filePath)

void	FlushEntireCache ()

void	CollectStatistics (AZStd::vector< Statistic > &statistics) const override

double	CalculateHitRatePercentage () const

double	CalculateCacheableRatePercentage () const

s32	CalculateAvailableRequestSlots () const

Public Member Functions inherited from AZ::IO::StreamStackEntry
	StreamStackEntry (AZStd::string &&name)

virtual const AZStd::string &	GetName () const
	Returns the name that uniquely identifies this entry.

virtual void	SetNext (AZStd::shared_ptr< StreamStackEntry > next)

virtual AZStd::shared_ptr< StreamStackEntry >	GetNext () const

virtual void	SetContext (StreamerContext &context)

virtual void	PrepareRequest (FileRequest *request)

virtual void	QueueRequest (FileRequest *request)

virtual bool	ExecuteRequests ()

virtual void	UpdateStatus (Status &status) const
	Gets a combined status update from all the nodes in the stack.

virtual void	UpdateCompletionEstimates (AZStd::chrono::steady_clock::time_point now, AZStd::vector< FileRequest * > &internalPending, StreamerContext::PreparedQueue::iterator pendingBegin, StreamerContext::PreparedQueue::iterator pendingEnd)

virtual void	CollectStatistics (AZStd::vector< Statistic > &statistics) const

Protected Types
enum class	CacheResult { ReadFromCache , CacheMiss , Queued , Delayed }

using	TimePoint = AZStd::chrono::steady_clock::time_point

Protected Member Functions
void	ReadFile (FileRequest *request, Requests::ReadData &data)

void	ContinueReadFile (FileRequest *request, u64 fileLength)

CacheResult	ReadFromCache (FileRequest *request, Section &section, const RequestPath &filePath)

CacheResult	ReadFromCache (FileRequest *request, Section &section, u32 cacheBlock)

CacheResult	ServiceFromCache (FileRequest *request, Section &section, const RequestPath &filePath, bool sharedRead)

void	CompleteRead (FileRequest &request)

bool	SplitRequest (Section &prolog, Section &main, Section &epilog, const RequestPath &filePath, u64 fileLength, u64 offset, u64 size, u8 *buffer) const

u8 *	GetCacheBlockData (u32 index)

void	TouchBlock (u32 index)

AZ::u32	RecycleOldestBlock (const RequestPath &filePath, u64 offset)

u32	FindInCache (const RequestPath &filePath, u64 offset) const

bool	IsCacheBlockInFlight (u32 index) const

void	ResetCacheEntry (u32 index)

void	ResetCache ()

void	Report (const Requests::ReportData &data) const

Protected Attributes
AZStd::unordered_multimap< FileRequest *, Section >	m_pendingRequests
	Map of the file requests that are being processed and the sections of the parent requests they'll complete.

AZStd::deque< Section >	m_delayedSections
	List of file sections that were delayed because the cache was full.

AZ::Statistics::RunningStatistic	m_hitRateStat

AZ::Statistics::RunningStatistic	m_cacheableStat

u8 *	m_cache

u64	m_cacheSize

u32	m_blockSize

u32	m_alignment

u32	m_numBlocks

s32	m_numInFlightRequests { 0 }

AZStd::unique_ptr< RequestPath[]>	m_cachedPaths
	The file path associated with a cache block.

AZStd::unique_ptr< u64[]>	m_cachedOffsets
	The offset into the file the cache blocks starts at.

AZStd::unique_ptr< TimePoint[]>	m_blockLastTouched
	The last time the cache block was read from.

AZStd::unique_ptr< FileRequest *[]>	m_inFlightRequests
	The file request that's currently read data into the cache block. If null, the block has been read.

s32	m_numMetaDataRetrievalInProgress { 0 }
	The number of requests waiting for meta data to be retrieved.

bool	m_onlyEpilogWrites
	Whether or not only the epilog ever writes to the cache.

Protected Attributes inherited from AZ::IO::StreamStackEntry
AZStd::string	m_name
	The name that uniquely identifies this entry.

AZStd::shared_ptr< StreamStackEntry >	m_next
	The next entry in the stack.

StreamerContext *	m_context
	Context information for the entire streaming stack.

Static Protected Attributes
static constexpr u32	s_fileNotCached = static_cast<u32>(-1)

Member Enumeration Documentation

◆ CacheResult

enum class AZ::IO::BlockCache::CacheResult

strongprotected

Enumerator
ReadFromCache	Data was found in the cache and reused.
CacheMiss	Data wasn't found in the cache and no sub request was queued.
Queued	A sub request was created or appended and queued for processing on the next entry in the streamer stack.
Delayed	There's no more room to queue a new request, so delay the request until a slot becomes available.

Member Function Documentation

◆ CollectStatistics()

void AZ::IO::BlockCache::CollectStatistics ( AZStd::vector< Statistic > & statistics ) const

overridevirtual

Collect various statistics on this stack entry. These are for profiling and debugging purposes only.

Reimplemented from AZ::IO::StreamStackEntry.

◆ ExecuteRequests()

bool AZ::IO::BlockCache::ExecuteRequests ( )

overridevirtual

Executes one or more queued requests. This is needed for synchronously executing requests, but asynchronous requests can already be running from the PrepareRequest call in which case this call is ignored.

Returns: True if a request was processed, otherwise false.

Reimplemented from AZ::IO::StreamStackEntry.

◆ QueueRequest()

void AZ::IO::BlockCache::QueueRequest ( FileRequest * request )

overridevirtual

Queues a request to be executed at a later point when ExecuteRequests is called. This can include splitting up the request in more fine-grained steps.

Reimplemented from AZ::IO::StreamStackEntry.

◆ UpdateCompletionEstimates()

void AZ::IO::BlockCache::UpdateCompletionEstimates	(	AZStd::chrono::steady_clock::time_point	now,
		AZStd::vector< FileRequest * > &	internalPending,
		StreamerContext::PreparedQueue::iterator	pendingBegin,
		StreamerContext::PreparedQueue::iterator	pendingEnd
	)

overridevirtual

Updates the estimate of the time the requests will complete. This generally works by bubbling up the estimation and each stack entry adding it's additional overhead if any. When chaining this call, first call the next entry in the stack before adding the current entry's estimate.

Parameters

now	The current time. This is captured once to avoid repeatedly querying the system clock.
internalPending	The requests that are pending in the stream stack. These are always estimated as coming after the queued requests. Because this call will go from the top of the stack to the bottom, but estimation is calculated from the bottom to the top, this list should be processed in reverse order.
pendingBegin	Iterator pointing to the start of the requests that are waiting for a processing slot in the stack.
pendingEnd	Iterator pointing to the end of the requests that are waiting for a processing slot in the stack.

Reimplemented from AZ::IO::StreamStackEntry.

◆ UpdateStatus()

void AZ::IO::BlockCache::UpdateStatus ( Status & status ) const

overridevirtual

Gets a combined status update from all the nodes in the stack.

Reimplemented from AZ::IO::StreamStackEntry.

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

Code/Framework/AzCore/AzCore/IO/Streamer/BlockCache.h

Classes

Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Static Protected Attributes

Member Enumeration Documentation

◆ CacheResult

Member Function Documentation

◆ CollectStatistics()

◆ ExecuteRequests()

◆ QueueRequest()

◆ UpdateCompletionEstimates()

◆ UpdateStatus()