Specialization of TTreeCache for parallel Unzipping.

Fabrizio Furano (CERN) Aug 2009 Core TTree-related code borrowed from the previous version by Leandro Franco and Rene Brun

Parallel Unzipping

TTreeCache has been specialised in order to let additional threads free to unzip in advance its content. In this implementation we support up to 10 threads, but right now it makes more sense to limit their number to 1-2

The application reading data is carefully synchronized, in order to:

if the block it wants is not unzipped, it self-unzips it without waiting
if the block is being unzipped in parallel, it waits only for that unzip to finish
if the block has already been unzipped, it takes it

This is supposed to cancel a part of the unzipping latency, at the expenses of cpu time.

The default parameters are the same of the prev version, i.e. 20% of the TTreeCache cache size. To change it use TTreeCache::SetUnzipBufferSize(Long64_t bufferSize) where bufferSize must be passed in bytes.

Definition at line 41 of file TTreeCacheUnzip.h.

Public Types
enum	EParUnzipMode { kEnable, kDisable, kForce }

Public Types inherited from TTreeCache
enum	EPrefillType { kNoPrefill, kAllBranches }

Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }

enum	EStatusBits { kCanDelete = BIT(0), kMustCleanup = BIT(3), kObjInCanvas = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5), kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13) }

Public Member Functions
	TTreeCacheUnzip ()

	TTreeCacheUnzip (TTree *tree, Int_t buffersize=0)
	Constructor. More...

virtual	~TTreeCacheUnzip ()
	Destructor. (in general called by the TFile destructor) More...

virtual Int_t	AddBranch (TBranch *b, Bool_t subbranches=kFALSE)
	Add a branch to the list of branches to be stored in the cache this function is called by TBranch::GetBasket Returns: More...

virtual Int_t	AddBranch (const char *branch, Bool_t subbranches=kFALSE)
	Add a branch to the list of branches to be stored in the cache this function is called by TBranch::GetBasket Returns: More...

Bool_t	FillBuffer ()
	Fill the cache buffer with the branches in the cache. More...

Int_t	GetNFound ()

Int_t	GetNMissed ()

Int_t	GetNUnzip ()

Int_t	GetRecordHeader (char *buf, Int_t maxbytes, Int_t &nbytes, Int_t &objlen, Int_t &keylen)
	Read the logical record header from the buffer buf. More...

virtual Int_t	GetUnzipBuffer (char *buf, Long64_t pos, Int_t len, Bool_t free)
	We try to read a buffer that has already been unzipped Returns -1 in case of read failure, 0 in case it's not in the cache and n>0 in case read from cache (number of bytes copied). More...

Bool_t	IsActiveThread ()
	This indicates if the thread is active in this moment... More...

Bool_t	IsQueueEmpty ()
	It says if the queue is empty... useful to see if we have to process it. More...

void	Print (Option_t *option="") const
	Print cache statistics. More...

virtual Int_t	ReadBufferExt (char *buf, Long64_t pos, Int_t len, Int_t &loc)

virtual void	ResetCache ()
	This will delete the list of buffers that are in the unzipping cache and will reset certain values in the cache. More...

void	SendUnzipStartSignal (Bool_t broadcast)
	This will send the signal corresponfing to the queue... More...

virtual Int_t	SetBufferSize (Int_t buffersize)
	Change the underlying buffer size of the cache. More...

void	SetEntryRange (Long64_t emin, Long64_t emax)
	Set the minimum and maximum entry number to be processed this information helps to optimize the number of baskets to read when prefetching the branch buffers. More...

void	SetUnzipBufferSize (Long64_t bufferSize)
	Sets the size for the unzipping cache... More...

virtual void	StopLearningPhase ()
	It's the same as TTreeCache::StopLearningPhase but we guarantee that we start the unzipping just after getting the buffers. More...

Int_t	UnzipBuffer (char *dest, char src)
	Unzips a ROOT specific buffer... More...

Int_t	UnzipCache (Int_t &startindex, Int_t &locbuffsz, char *&locbuff)
	This inflates all the buffers in the cache. More...

void	UpdateBranches (TTree *tree)
	update pointer to current Tree and recompute pointers to the branches in the cache More...

void	WaitUnzipStartSignal ()

Public Member Functions inherited from TTreeCache
	TTreeCache ()
	Default Constructor. More...

	TTreeCache (TTree *tree, Int_t buffersize=0)
	Constructor. More...

virtual	~TTreeCache ()
	Destructor. (in general called by the TFile destructor) More...

virtual void	Disable ()

virtual Int_t	DropBranch (TBranch *b, Bool_t subbranches=kFALSE)
	Remove a branch to the list of branches to be stored in the cache this function is called by TBranch::GetBasket. More...

virtual Int_t	DropBranch (const char *branch, Bool_t subbranches=kFALSE)
	Remove a branch to the list of branches to be stored in the cache this is to be used by user (thats why we pass the name of the branch). More...

virtual void	Enable ()

const TObjArray *	GetCachedBranches () const

EPrefillType	GetConfiguredPrefillType () const
	Return the desired prefill type from the environment or resource variable. More...

Double_t	GetEfficiency () const
	Give the total efficiency of the cache... More...

Double_t	GetEfficiencyRel () const
	This will indicate a sort of relative efficiency... More...

virtual Int_t	GetEntryMax () const

virtual Int_t	GetEntryMin () const

virtual EPrefillType	GetLearnPrefill () const

TTree *	GetTree () const

Bool_t	IsAutoCreated () const

virtual Bool_t	IsEnabled () const

virtual Bool_t	IsLearning () const

virtual void	LearnPrefill ()
	Perform an initial prefetch, attempting to read as much of the learning phase baskets for all branches at once. More...

virtual Int_t	ReadBuffer (char *buf, Long64_t pos, Int_t len)
	Read buffer at position pos if the request is in the list of prefetched blocks read from fBuffer. More...

virtual Int_t	ReadBufferNormal (char *buf, Long64_t pos, Int_t len)
	Old method ReadBuffer before the addition of the prefetch mechanism. More...

virtual Int_t	ReadBufferPrefetch (char *buf, Long64_t pos, Int_t len)
	Used to read a chunk from a block previously fetched. More...

void	SetAutoCreated (Bool_t val)

virtual void	SetFile (TFile *file, TFile::ECacheAction action=TFile::kDisconnect)
	Overload to make sure that the object specific. More...

virtual void	SetLearnPrefill (EPrefillType type=kNoPrefill)
	Set whether the learning period is started with a prefilling of the cache and which type of prefilling is used. More...

void	StartLearningPhase ()
	The name should be enough to explain the method. More...

Public Member Functions inherited from TFileCacheRead
	TFileCacheRead ()
	Default Constructor. More...

	TFileCacheRead (TFile file, Int_t buffersize, TObject tree=0)
	Creates a TFileCacheRead data structure. More...

virtual	~TFileCacheRead ()
	Destructor. More...

virtual void	AddNoCacheBytesRead (Long64_t len)

virtual void	AddNoCacheReadCalls (Int_t reads)

virtual void	Close (Option_t *option="")
	Close out any threads or asynchronous fetches used by the underlying implementation. More...

virtual Int_t	GetBufferSize () const

virtual Long64_t	GetBytesRead () const

virtual Long64_t	GetBytesReadExtra () const

TFile *	GetFile () const

virtual Long64_t	GetNoCacheBytesRead () const

virtual Int_t	GetNoCacheReadCalls () const

Int_t	GetNseek () const

Int_t	GetNtot () const

Long64_t	GetPrefetchedBlocks () const

virtual TFilePrefetch *	GetPrefetchObj ()

virtual Int_t	GetReadCalls () const

virtual Bool_t	IsAsyncReading () const

virtual Bool_t	IsEnablePrefetching () const

virtual void	Prefetch (Long64_t pos, Int_t len)
	Add block of length len at position pos in the list of blocks to be prefetched. More...

virtual Int_t	ReadBufferExtNormal (char *buf, Long64_t pos, Int_t len, Int_t &loc)
	Base function for ReadBuffer. More...

virtual Int_t	ReadBufferExtPrefetch (char *buf, Long64_t pos, Int_t len, Int_t &loc)
	prefetch the first block More...

virtual void	SecondPrefetch (Long64_t, Int_t)

virtual void	SecondSort ()
	Sort buffers to be prefetched in increasing order of positions. More...

virtual void	SetEnablePrefetching (Bool_t setPrefetching=kFALSE)
	Set the prefetching mode of this file. More...

virtual void	SetSkipZip (Bool_t=kTRUE)

virtual void	Sort ()
	Sort buffers to be prefetched in increasing order of positions. More...

virtual void	WaitFinishPrefetch ()

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor. More...

	TObject (const TObject &object)
	TObject copy ctor. More...

virtual	~TObject ()
	TObject destructor. More...

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad. More...

virtual void	Browse (TBrowser *b)
	Browse object. May be overridden for another default action. More...

virtual const char *	ClassName () const
	Returns name of class to which the object belongs. More...

virtual void	Clear (Option_t *="")

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility. More...

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method. More...

virtual void	Copy (TObject &object) const
	Copy this to obj. More...

virtual void	Delete (Option_t *option="")
	Delete this object. More...

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object. More...

virtual void	Draw (Option_t *option="")
	Default Draw method for all objects. More...

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs. More...

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current pad. More...

virtual void	Dump () const
	Dump contents of object on stdout. More...

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message. More...

virtual void	Execute (const char method, const char params, Int_t *error=0)
	Execute method on this object with the given parameter string, e.g. More...

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray. More...

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py). More...

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message. More...

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes. More...

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes. More...

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object. More...

virtual const char *	GetIconName () const
	Returns mime type name of object. More...

virtual const char *	GetName () const
	Returns name of object. More...

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py). More...

virtual Option_t *	GetOption () const

virtual const char *	GetTitle () const
	Returns title of object. More...

virtual UInt_t	GetUniqueID () const
	Return the unique object id. More...

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out. More...

virtual ULong_t	Hash () const
	Return hash value for this object. More...

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message. More...

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname". More...

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl. More...

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas. More...

void	InvertBit (UInt_t f)

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory). More...

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...

Bool_t	IsOnHeap () const

virtual Bool_t	IsSortable () const

Bool_t	IsZombie () const

virtual void	ls (Option_t *option="") const
	The ls function lists the contents of a class on stdout. More...

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification. More...

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete. More...

void	operator delete (void *ptr)
	Operator delete. More...

void	operator delete[] (void *ptr)
	Operator delete []. More...

void *	operator new (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, void *vp)

TObject &	operator= (const TObject &rhs)
	TObject assignment operator. More...

virtual void	Paint (Option_t *option="")
	This method must be overridden if a class wants to paint itself. More...

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list. More...

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory. More...

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list. More...

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename. More...

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out". More...

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f. More...

void	SetBit (UInt_t f)

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object. More...

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id. More...

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message. More...

Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory. More...

Static Public Member Functions
static EParUnzipMode	GetParallelUnzip ()
	Static function that returns the parallel option (to indicate an additional thread) More...

static Bool_t	IsParallelUnzip ()
	Static function that tells wether the multithreading unzipping is activated. More...

static Int_t	SetParallelUnzip (TTreeCacheUnzip::EParUnzipMode option=TTreeCacheUnzip::kEnable)
	Static function that (de)activates multithreading unzipping. More...

static void	SetUnzipRelBufferSize (Float_t relbufferSize)
	static function: Sets the unzip relatibe buffer size More...

static void *	UnzipLoop (void *arg)
	This is a static function. More...

Static Public Member Functions inherited from TTreeCache
static Int_t	GetLearnEntries ()
	Static function returning the number of entries used to train the cache see SetLearnEntries. More...

static void	SetLearnEntries (Int_t n=10)
	Static function to set the number of entries to be used in learning mode The default value for n is 10. More...

Static Public Member Functions inherited from TObject
static Long_t	GetDtorOnly ()
	Return destructor only flag. More...

static Bool_t	GetObjectStat ()
	Get status of object stat flag. More...

static void	SetDtorOnly (void *obj)
	Set destructor only flag. More...

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable. More...

Protected Attributes
std::queue< Int_t >	fActiveBlks
	The blocks which are active now. More...

Bool_t	fActiveThread
	Used to terminate gracefully the unzippers. More...

Bool_t	fAsyncReading

Int_t	fBlocksToGo

Int_t	fCycle

TMutex *	fIOMutex

Int_t	fLastReadPos

TMutex *	fMutexList
	Mutex to protect the various lists. Used by the condvars. More...

Int_t	fNFound
	! number of blocks that were found in the cache More...

Int_t	fNMissed
	! number of blocks that were not found in the cache and were unzipped More...

Int_t	fNseekMax
	! fNseek can change so we need to know its max size More...

Int_t	fNStalls
	! number of hits which caused a stall More...

Int_t	fNUnzip
	! number of blocks that were unzipped More...

Bool_t	fParallel
	Indicate if we want to activate the parallelism (for this instance) More...

Long64_t	fTotalUnzipBytes
	! The total sum of the currently unzipped blks More...

Long64_t	fUnzipBufferSize
	! Max Size for the ready unzipped blocks (default is 2*fBufferSize) More...

char **	fUnzipChunks
	! [fNseek] Individual unzipped chunks. Their summed size is kept under control. More...

TCondition *	fUnzipDoneCondition
	Used to wait for an unzip tour to finish. Gives the Async feel. More...

Int_t *	fUnzipLen
	! [fNseek] Length of the unzipped buffers More...

TCondition *	fUnzipStartCondition
	Used to signal the threads to start. More...

Byte_t *	fUnzipStatus
	! [fNSeek] For each blk, tells us if it's unzipped or pending More...

TThread *	fUnzipThread [10]

Protected Attributes inherited from TTreeCache
Bool_t	fAutoCreated
	! true if cache was automatically created More...

TObjArray *	fBranches
	! List of branches to be stored in the cache More...

TList *	fBrNames
	! list of branch names in the cache More...

Bool_t	fEnabled
	! cache enabled for cached reading More...

Long64_t	fEntryCurrent
	! current lowest entry number in the cache More...

Long64_t	fEntryMax
	! last entry in the cache More...

Long64_t	fEntryMin
	! first entry in the cache More...

Long64_t	fEntryNext
	! next entry number where cache must be filled More...

Int_t	fFillTimes
	! how many times we can fill the current buffer More...

Bool_t	fFirstBuffer
	! true if first buffer is used for prefetching More...

Long64_t	fFirstEntry
	! save the value of the first entry More...

Bool_t	fFirstTime
	! save the fact that we processes the first entry More...

Bool_t	fIsLearning
	! true if cache is in learning mode More...

Bool_t	fIsManual
	! true if cache is StopLearningPhase was used More...

Int_t	fNbranches
	! Number of branches in the cache More...

Int_t	fNReadMiss
	Number of blocks read and not found in the cache. More...

Int_t	fNReadOk
	Number of blocks read and found in the cache. More...

Int_t	fNReadPref
	Number of blocks that were prefetched. More...

Bool_t	fOneTime
	! used in the learning phase More...

EPrefillType	fPrefillType
	Whether a pre-filling is enabled (and if applicable which type) More...

Bool_t	fReadDirectionSet
	! read direction established More...

Bool_t	fReverseRead
	! reading in reverse mode More...

TTree *	fTree
	! pointer to the current Tree More...

Protected Attributes inherited from TFileCacheRead
Bool_t	fAsyncReading

Bool_t	fBIsSorted

Bool_t	fBIsTransferred

Int_t *	fBLen
	[fBNb] More...

Int_t	fBNb

Int_t	fBNseek

Int_t	fBNtot

Long64_t *	fBPos
	[fBNb] More...

Long64_t *	fBSeek
	[fBNseek] More...

Int_t *	fBSeekIndex
	[fBNseek] More...

Int_t *	fBSeekLen
	[fBNseek] More...

Int_t *	fBSeekPos
	[fBNseek] More...

Int_t	fBSeekSize

Long64_t *	fBSeekSort
	[fBNseek] More...

Int_t *	fBSeekSortLen
	[fBNseek] More...

char *	fBuffer
	[fBufferSize] buffer of contiguous prefetched blocks More...

Int_t	fBufferLen
	Current buffer length (<= fBufferSize) More...

Int_t	fBufferSize
	Allocated size of fBuffer (at a given time) More...

Int_t	fBufferSizeMin
	Original size of fBuffer. More...

Long64_t	fBytesRead
	Number of bytes read for this cache. More...

Long64_t	fBytesReadExtra
	Number of extra bytes (overhead) read by the readahead buffer. More...

Bool_t	fEnablePrefetching
	reading by prefetching asynchronously More...

TFile *	fFile
	Pointer to file. More...

Bool_t	fIsSorted
	True if fSeek array is sorted. More...

Bool_t	fIsTransferred
	True when fBuffer contains something valid. More...

Int_t *	fLen
	[fNb] Length of long buffers More...

Int_t	fNb
	Number of long buffers. More...

Long64_t	fNoCacheBytesRead
	Number of bytes read by basket to fill cached tree. More...

Int_t	fNoCacheReadCalls
	Number of read calls by basket to fill cached tree. More...

Int_t	fNseek
	Number of blocks to be prefetched. More...

Int_t	fNtot
	Total size of prefetched blocks. More...

Long64_t *	fPos
	[fNb] start of long buffers More...

TFilePrefetch *	fPrefetch
	! Object that does the asynchronous reading in another thread More...

Long64_t	fPrefetchedBlocks
	Number of blocks prefetched. More...

Int_t	fReadCalls
	Number of read calls for this cache. More...

Long64_t *	fSeek
	[fNseek] Position on file of buffers to be prefetched More...

Int_t *	fSeekIndex
	[fNseek] sorted index table of fSeek More...

Int_t *	fSeekLen
	[fNseek] Length of buffers to be prefetched More...

Int_t *	fSeekPos
	[fNseek] Position of sorted blocks in fBuffer More...

Int_t	fSeekSize
	Allocated size of fSeek. More...

Long64_t *	fSeekSort
	[fNseek] Position on file of buffers to be prefetched (sorted) More...

Int_t *	fSeekSortLen
	[fNseek] Length of buffers to be prefetched (sorted) More...

Static Protected Attributes
static TTreeCacheUnzip::EParUnzipMode	fgParallel = TTreeCacheUnzip::kDisable
	Indicate if we want to activate the parallelism. More...

static Double_t	fgRelBuffSize = .5
	This is the percentage of the TTreeCacheUnzip that will be used. More...

Static Protected Attributes inherited from TTreeCache
static Int_t	fgLearnEntries = 100
	number of entries used for learning mode More...

Private Member Functions
	TTreeCacheUnzip (const TTreeCacheUnzip &)

void	Init ()
	Initialization procedure common to all the constructors. More...

TTreeCacheUnzip &	operator= (const TTreeCacheUnzip &)

Int_t	StartThreadUnzip (Int_t nthreads)
	The Thread is only a part of the TTreeCache but it is the part that waits for info in the queue and process it... More...

Int_t	StopThreadUnzip ()
	To stop the thread we only need to change the value of the variable fActiveThread to false and the loop will stop (of course, we will have) to do the cleaning after that. More...

Private Attributes
char *	fCompBuffer

Int_t	fCompBufferSize

Additional Inherited Members
Protected Member Functions inherited from TFileCacheRead
void	SetEnablePrefetchingImpl (Bool_t setPrefetching=kFALSE)
	TFileCacheRead implementation of SetEnablePrefetching. More...

Protected Member Functions inherited from TObject
virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected). More...

void	MakeZombie ()

#include <TTreeCacheUnzip.h>

Inheritance diagram for TTreeCacheUnzip:

[legend]

Member Enumeration Documentation

enum TTreeCacheUnzip::EParUnzipMode

Enumerator
kEnable
kDisable
kForce

Definition at line 45 of file TTreeCacheUnzip.h.

Constructor & Destructor Documentation

TTreeCacheUnzip::TTreeCacheUnzip ( const TTreeCacheUnzip & )

private

TTreeCacheUnzip::TTreeCacheUnzip ( )

Definition at line 73 of file TTreeCacheUnzip.cxx.

TTreeCacheUnzip::TTreeCacheUnzip	(	TTree *	tree,
		Int_t	buffersize = `0`
	)

Constructor.

Definition at line 100 of file TTreeCacheUnzip.cxx.

TTreeCacheUnzip::~TTreeCacheUnzip ( )

virtual

Destructor. (in general called by the TFile destructor)

Definition at line 170 of file TTreeCacheUnzip.cxx.

Member Function Documentation

Int_t TTreeCacheUnzip::AddBranch	(	TBranch *	b,
		Bool_t	subbranches = `kFALSE`
	)

virtual

Add a branch to the list of branches to be stored in the cache this function is called by TBranch::GetBasket Returns:

0 branch added or already included
-1 on error

Reimplemented from TTreeCache.

Definition at line 196 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::AddBranch	(	const char *	branch,
		Bool_t	subbranches = `kFALSE`
	)

virtual

Add a branch to the list of branches to be stored in the cache this function is called by TBranch::GetBasket Returns:

0 branch added or already included
-1 on error

Reimplemented from TTreeCache.

Definition at line 210 of file TTreeCacheUnzip.cxx.

Bool_t TTreeCacheUnzip::FillBuffer ( )

virtual

Fill the cache buffer with the branches in the cache.

Reimplemented from TTreeCache.

Definition at line 219 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::GetNFound ( )

inline

Definition at line 131 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::GetNMissed ( )

inline

Definition at line 132 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::GetNUnzip ( )

inline

Definition at line 130 of file TTreeCacheUnzip.h.

TTreeCacheUnzip::EParUnzipMode TTreeCacheUnzip::GetParallelUnzip ( )

static

Static function that returns the parallel option (to indicate an additional thread)

Definition at line 371 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::GetRecordHeader	(	char *	buf,
		Int_t	maxbytes,
		Int_t &	nbytes,
		Int_t &	objlen,
		Int_t &	keylen
	)

Read the logical record header from the buffer buf.

That must be the pointer tho the header part not the object by itself and must contain data of at least maxbytes Returns nread;

In output arguments:

nbytes : number of bytes in record if negative, this is a deleted record if 0, cannot read record, wrong value of argument first
objlen : uncompressed object size
keylen : length of logical record header

Note that the arguments objlen and keylen are returned only if maxbytes >=16 Note: This was adapted from TFile... so some things dont apply

Definition at line 611 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::GetUnzipBuffer	(	char **	buf,
		Long64_t	pos,
		Int_t	len,
		Bool_t *	free
	)

virtual

We try to read a buffer that has already been unzipped Returns -1 in case of read failure, 0 in case it's not in the cache and n>0 in case read from cache (number of bytes copied).

pos and len are the original values as were passed to ReadBuffer but instead we will return the inflated buffer. Note!! : If *buf == 0 we will allocate the buffer and it will be the responsability of the caller to free it... it is useful for example to pass it to the creator of TBuffer

Reimplemented from TFileCacheRead.

Definition at line 708 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::Init ( void )

private

Initialization procedure common to all the constructors.

Definition at line 123 of file TTreeCacheUnzip.cxx.

Bool_t TTreeCacheUnzip::IsActiveThread ( )

This indicates if the thread is active in this moment...

this variable is very important because if we change it from true to false the thread will stop... ( see StopThreadTreeCacheUnzip() )

Definition at line 392 of file TTreeCacheUnzip.cxx.

Bool_t TTreeCacheUnzip::IsParallelUnzip ( )

static

Static function that tells wether the multithreading unzipping is activated.

Definition at line 379 of file TTreeCacheUnzip.cxx.

Bool_t TTreeCacheUnzip::IsQueueEmpty ( )

It says if the queue is empty... useful to see if we have to process it.

Definition at line 402 of file TTreeCacheUnzip.cxx.

TTreeCacheUnzip& TTreeCacheUnzip::operator= ( const TTreeCacheUnzip & )

private

void TTreeCacheUnzip::Print ( Option_t * option = "" ) const

virtual

Print cache statistics.

Like:

******TreeCache statistics for file: cms2.root ******
Number of branches in the cache ...: 1093
Cache Efficiency ..................: 0.997372
Cache Efficiency Rel...............: 1.000000
Learn entries......................: 100
Reading............................: 72761843 bytes in 7 transactions
Readahead..........................: 256000 bytes with overhead = 0 bytes
Average transaction................: 10394.549000 Kbytes
Number of blocks in current cache..: 210, total size: 6280352

if option = "a" the list of blocks in the cache is printed see also class TTreePerfStats.
if option contains 'cachedbranches', the list of branches being cached is printed.

Reimplemented from TTreeCache.

Definition at line 1245 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::ReadBufferExt	(	char *	buf,
		Long64_t	pos,
		Int_t	len,
		Int_t &	loc
	)

virtual

Reimplemented from TFileCacheRead.

Definition at line 1259 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::ResetCache ( )

virtual

This will delete the list of buffers that are in the unzipping cache and will reset certain values in the cache.

This name is ambiguos because the method doesn't reset the whole cache, only the part related to the unzipping Note: This method is completely different from TTreeCache::ResetCache(), in that method we were cleaning the prefetching buffer while here we delete the information about the unzipped buffers

Reimplemented from TTreeCache.

Definition at line 643 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::SendUnzipStartSignal ( Bool_t broadcast )

This will send the signal corresponfing to the queue...

normally used when we want to start processing the list of buffers.

Definition at line 424 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::SetBufferSize ( Int_t buffersize )

virtual

Change the underlying buffer size of the cache.

Returns:

0 if the buffer content is still available
1 if some or all of the buffer content has been made unavailable
-1 on error

Reimplemented from TTreeCache.

Definition at line 314 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::SetEntryRange	(	Long64_t	emin,
		Long64_t	emax
	)

virtual

Set the minimum and maximum entry number to be processed this information helps to optimize the number of baskets to read when prefetching the branch buffers.

Reimplemented from TTreeCache.

Definition at line 332 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::SetParallelUnzip ( TTreeCacheUnzip::EParUnzipMode option = TTreeCacheUnzip::kEnable )

static

Static function that (de)activates multithreading unzipping.

The possible options are:

kEnable Enable it, which causes an automatic detection and launches the additional thread if the number of cores in the machine is greater than one
kDisable Disable will not activate the additional thread.
kForce Force will start the additional thread even if there is only one core. the default will be taken as kEnable.

Returns 0 if there was an error, 1 otherwise.

Definition at line 447 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::SetUnzipBufferSize ( Long64_t bufferSize )

Sets the size for the unzipping cache...

by default it should be two times the size of the prefetching cache

Definition at line 931 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::SetUnzipRelBufferSize ( Float_t relbufferSize )

static

static function: Sets the unzip relatibe buffer size

Definition at line 922 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::StartThreadUnzip ( Int_t nthreads )

private

The Thread is only a part of the TTreeCache but it is the part that waits for info in the queue and process it...

unfortunatly, a Thread is not an object an we have to deal with it in the old C-Style way Returns 0 if the thread was initialized or 1 if it was already running

Definition at line 468 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::StopLearningPhase ( )

virtual

It's the same as TTreeCache::StopLearningPhase but we guarantee that we start the unzipping just after getting the buffers.

Reimplemented from TTreeCache.

Definition at line 343 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::StopThreadUnzip ( )

private

To stop the thread we only need to change the value of the variable fActiveThread to false and the loop will stop (of course, we will have) to do the cleaning after that.

Note: The syncronization part is important here or we will try to delete teh object while it's still processing the queue

Definition at line 511 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::UnzipBuffer	(	char **	dest,
		char *	src
	)

Unzips a ROOT specific buffer...

by reading the header at the beginning. returns the size of the inflated buffer or -1 if error Note!! : If *dest == 0 we will allocate the buffer and it will be the responsability of the caller to free it... it is useful for example to pass it to the creator of TBuffer src is the original buffer with the record (header+compressed data) *dest is the inflated buffer (including the header)

Definition at line 947 of file TTreeCacheUnzip.cxx.

Int_t TTreeCacheUnzip::UnzipCache	(	Int_t &	startindex,
		Int_t &	locbuffsz,
		char *&	locbuff
	)

This inflates all the buffers in the cache.

. passing the data to a new buffer that will only wait there to be read... We can not inflate all the buffers in the cache so we will try to do it until the cache gets full... there is a member called fUnzipBufferSize which will tell us the max size we can allocate for this cache.

note that we will unzip in the order they were put into the cache not the order of the transference so it has to be read in that order or the pre-unzipping will be useless.

startindex is used as start index to check for blks to be unzipped

returns 0 in normal conditions or -1 if error, 1 if it would like to sleep

This func is supposed to compete among an indefinite number of threads to get a chunk to inflate in order to accommodate multiple unzippers Since everything is so async, we cannot use a fixed buffer, we are forced to keep the individual chunks as separate blocks, whose summed size does not exceed the maximum allowed. The pointers are kept globally in the array fUnzipChunks

Definition at line 1060 of file TTreeCacheUnzip.cxx.

void * TTreeCacheUnzip::UnzipLoop ( void * arg )

static

This is a static function.

This is the call that will be executed in the Thread generated by StartThreadTreeCacheUnzip... what we want to do is to inflate the next series of buffers leaving them in the second cache.

Returns 0 when it finishes

Definition at line 540 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::UpdateBranches ( TTree * tree )

virtual

update pointer to current Tree and recompute pointers to the branches in the cache

Reimplemented from TTreeCache.

Definition at line 354 of file TTreeCacheUnzip.cxx.

void TTreeCacheUnzip::WaitUnzipStartSignal ( )

Definition at line 412 of file TTreeCacheUnzip.cxx.

Member Data Documentation

std::queue<Int_t> TTreeCacheUnzip::fActiveBlks

protected

The blocks which are active now.

Definition at line 82 of file TTreeCacheUnzip.h.

Bool_t TTreeCacheUnzip::fActiveThread

protected

Used to terminate gracefully the unzippers.

Definition at line 51 of file TTreeCacheUnzip.h.

Bool_t TTreeCacheUnzip::fAsyncReading

protected

Definition at line 55 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fBlocksToGo

protected

Definition at line 63 of file TTreeCacheUnzip.h.

char* TTreeCacheUnzip::fCompBuffer

private

Definition at line 88 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fCompBufferSize

private

Definition at line 89 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fCycle

protected

Definition at line 59 of file TTreeCacheUnzip.h.

TTreeCacheUnzip::EParUnzipMode TTreeCacheUnzip::fgParallel = TTreeCacheUnzip::kDisable

staticprotected

Indicate if we want to activate the parallelism.

Definition at line 60 of file TTreeCacheUnzip.h.

Double_t TTreeCacheUnzip::fgRelBuffSize = .5

staticprotected

This is the percentage of the TTreeCacheUnzip that will be used.

Definition at line 74 of file TTreeCacheUnzip.h.

TMutex* TTreeCacheUnzip::fIOMutex

protected

Definition at line 57 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fLastReadPos

protected

Definition at line 62 of file TTreeCacheUnzip.h.

TMutex* TTreeCacheUnzip::fMutexList

protected

Mutex to protect the various lists. Used by the condvars.

Definition at line 56 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fNFound

protected

! number of blocks that were found in the cache

Definition at line 78 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fNMissed

protected

! number of blocks that were not found in the cache and were unzipped

Definition at line 80 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fNseekMax

protected

! fNseek can change so we need to know its max size

Definition at line 71 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fNStalls

protected

! number of hits which caused a stall

Definition at line 79 of file TTreeCacheUnzip.h.

Int_t TTreeCacheUnzip::fNUnzip

protected

! number of blocks that were unzipped

Definition at line 77 of file TTreeCacheUnzip.h.

Bool_t TTreeCacheUnzip::fParallel

protected

Indicate if we want to activate the parallelism (for this instance)

Definition at line 54 of file TTreeCacheUnzip.h.

Long64_t TTreeCacheUnzip::fTotalUnzipBytes

protected

! The total sum of the currently unzipped blks

Definition at line 69 of file TTreeCacheUnzip.h.

Long64_t TTreeCacheUnzip::fUnzipBufferSize

protected

! Max Size for the ready unzipped blocks (default is 2*fBufferSize)

Definition at line 72 of file TTreeCacheUnzip.h.

char** TTreeCacheUnzip::fUnzipChunks

protected

! [fNseek] Individual unzipped chunks. Their summed size is kept under control.

Definition at line 67 of file TTreeCacheUnzip.h.

TCondition* TTreeCacheUnzip::fUnzipDoneCondition

protected

Used to wait for an unzip tour to finish. Gives the Async feel.

Definition at line 53 of file TTreeCacheUnzip.h.

Int_t* TTreeCacheUnzip::fUnzipLen

protected

! [fNseek] Length of the unzipped buffers

Definition at line 66 of file TTreeCacheUnzip.h.

TCondition* TTreeCacheUnzip::fUnzipStartCondition

protected

Used to signal the threads to start.

Definition at line 52 of file TTreeCacheUnzip.h.

Byte_t* TTreeCacheUnzip::fUnzipStatus

protected

! [fNSeek] For each blk, tells us if it's unzipped or pending

Definition at line 68 of file TTreeCacheUnzip.h.

TThread* TTreeCacheUnzip::fUnzipThread[10]

protected

Definition at line 50 of file TTreeCacheUnzip.h.

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

tree/tree/inc/TTreeCacheUnzip.h
tree/tree/src/TTreeCacheUnzip.cxx

Parallel Unzipping

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