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TTreeCache.h
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1// @(#)root/tree:$Id$
2// Author: Rene Brun 04/06/2006
3
4/*************************************************************************
5 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *
6 * All rights reserved. *
7 * *
8 * For the licensing terms see $ROOTSYS/LICENSE. *
9 * For the list of contributors see $ROOTSYS/README/CREDITS. *
10 *************************************************************************/
11
12#ifndef ROOT_TTreeCache
13#define ROOT_TTreeCache
14
15
16//////////////////////////////////////////////////////////////////////////
17// //
18// TTreeCache //
19// //
20// Specialization of TFileCacheRead for a TTree //
21// //
22//////////////////////////////////////////////////////////////////////////
23
24#include "TFileCacheRead.h"
25
26#include <vector>
27
28class TTree;
29class TBranch;
30class TObjArray;
31
32class TTreeCache : public TFileCacheRead {
33
34public:
36
37protected:
38 Long64_t fEntryMin{0}; ///<! first entry in the cache
39 Long64_t fEntryMax{1}; ///<! last entry in the cache
40 Long64_t fEntryCurrent{-1}; ///<! current lowest entry number in the cache
41 Long64_t fEntryNext{-1}; ///<! next entry number where cache must be filled
42 Long64_t fCurrentClusterStart{-1}; ///<! Start of the cluster(s) where the current content was picked out
43 Long64_t fNextClusterStart{-1}; ///<! End+1 of the cluster(s) where the current content was picked out
44 Int_t fNbranches{0}; ///<! Number of branches in the cache
45 Int_t fNReadOk{0}; ///< Number of blocks read and found in the cache
46 Int_t fNMissReadOk{0}; ///< Number of blocks read, not found in the primary cache, and found in the secondary cache.
47 Int_t fNReadMiss{0}; ///< Number of blocks read and not found in the cache
48 Int_t fNMissReadMiss{0}; ///< Number of blocks read and not found in either cache.
49 Int_t fNReadPref{0}; ///< Number of blocks that were prefetched
50 Int_t fNMissReadPref{0}; ///< Number of blocks read into the secondary ("miss") cache.
51 TObjArray *fBranches{nullptr}; ///<! List of branches to be stored in the cache
52 TList *fBrNames{nullptr}; ///<! list of branch names in the cache
53 TTree *fTree{nullptr}; ///<! pointer to the current Tree
54 Bool_t fIsLearning{kTRUE}; ///<! true if cache is in learning mode
55 Bool_t fIsManual{kFALSE}; ///<! true if cache is StopLearningPhase was used
56 Bool_t fFirstBuffer{kTRUE}; ///<! true if first buffer is used for prefetching
57 Bool_t fOneTime{kFALSE}; ///<! used in the learning phase
58 Bool_t fReverseRead{kFALSE}; ///<! reading in reverse mode
59 Int_t fFillTimes{0}; ///<! how many times we can fill the current buffer
60 Bool_t fFirstTime{kTRUE}; ///<! save the fact that we processes the first entry
61 Long64_t fFirstEntry{-1}; ///<! save the value of the first entry
62 Bool_t fReadDirectionSet{kFALSE}; ///<! read direction established
63 Bool_t fEnabled{kTRUE}; ///<! cache enabled for cached reading
64 EPrefillType fPrefillType; ///< Whether a pre-filling is enabled (and if applicable which type)
65 static Int_t fgLearnEntries; ///< number of entries used for learning mode
66 Bool_t fAutoCreated{kFALSE}; ///<! true if cache was automatically created
67
68 Bool_t fLearnPrefilling{kFALSE}; ///<! true if we are in the process of executing LearnPrefill
69
70 // These members hold cached data for missed branches when miss optimization
71 // is enabled. Pointers are only initialized if the miss cache is enabled.
72 Bool_t fOptimizeMisses{kFALSE}; ///<! true if we should optimize cache misses.
73 Long64_t fFirstMiss{-1}; ///<! set to the event # of the first miss.
74 Long64_t fLastMiss{-1}; ///<! set to the event # of the last miss.
75
76 // Representation of a positioned buffer IO.
77 // {0,0} designates the uninitialized - or invalid - buffer.
78 struct IOPos {
79 IOPos(Long64_t pos, Int_t len) : fPos(pos), fLen(len) {}
80
81 Long64_t fPos{0}; //! Position in file of cache entry.
82 Int_t fLen{0}; //! Length of cache entry.
83 };
84
85 struct MissCache {
86 struct Entry {
87 Entry(IOPos io) : fIO(io) {}
88
90 ULong64_t fIndex{0}; ///<! Location in fData corresponding to this entry.
91 friend bool operator<(const Entry &a, const Entry &b) { return a.fIO.fPos < b.fIO.fPos; }
92 };
93 std::vector<Entry> fEntries; ///<! Description of buffers in the miss cache.
94 std::vector<TBranch *> fBranches; ///<! list of branches that we read on misses.
95 std::vector<char> fData; ///<! Actual data in the cache.
96
97 void clear()
98 {
99 fEntries.clear();
100 fBranches.clear();
101 fData.clear();
102 }
103 };
104
105 std::unique_ptr<MissCache> fMissCache; ///<! Cache contents for misses
106
107private:
108 TTreeCache(const TTreeCache &) = delete; ///< this class cannot be copied
109 TTreeCache &operator=(const TTreeCache &) = delete;
110
111 // These are all functions related to the "miss cache": this attempts to
112 // optimize ROOT's behavior when the TTreeCache has a cache miss. In this
113 // case, we try to read several branches for the event with the miss.
114 //
115 // The miss cache is more CPU-intensive than the rest of the TTreeCache code;
116 // for local work (i.e., laptop with SSD), this CPU cost may outweight the
117 // benefit.
118 Bool_t CheckMissCache(char *buf, Long64_t pos,
119 int len); ///< Check the miss cache for a particular buffer, fetching if deemed necessary.
120 Bool_t FillMissCache(); ///< Fill the miss cache from the current set of active branches.
121 Bool_t CalculateMissCache(); ///< Calculate the appropriate miss cache to fetch; helper function for FillMissCache
122 IOPos FindBranchBasketPos(TBranch &, Long64_t entry); ///< Given a branch and an entry, determine the file location
123 ///< (offset / size) of the corresponding basket.
124 TBranch *CalculateMissEntries(Long64_t, int, bool); ///< Given an file read, try to determine the corresponding branch.
125 Bool_t ProcessMiss(Long64_t pos, int len); ///<! Given a file read not in the miss cache, handle (possibly) loading the data.
126
127public:
128
129 TTreeCache();
130 TTreeCache(TTree *tree, Int_t buffersize=0);
131 virtual ~TTreeCache();
132 virtual Int_t AddBranch(TBranch *b, Bool_t subgbranches = kFALSE);
133 virtual Int_t AddBranch(const char *branch, Bool_t subbranches = kFALSE);
134 virtual Int_t DropBranch(TBranch *b, Bool_t subbranches = kFALSE);
135 virtual Int_t DropBranch(const char *branch, Bool_t subbranches = kFALSE);
136 virtual void Disable() {fEnabled = kFALSE;}
137 virtual void Enable() {fEnabled = kTRUE;}
139 const TObjArray *GetCachedBranches() const { return fBranches; }
141 Double_t GetEfficiency() const;
143 virtual Int_t GetEntryMin() const {return fEntryMin;}
144 virtual Int_t GetEntryMax() const {return fEntryMax;}
145 static Int_t GetLearnEntries();
146 virtual EPrefillType GetLearnPrefill() const {return fPrefillType;}
149 TTree *GetTree() const {return fTree;}
151 virtual Bool_t IsEnabled() const {return fEnabled;}
152 virtual Bool_t IsLearning() const {return fIsLearning;}
153
154 virtual Bool_t FillBuffer();
155 virtual Int_t LearnBranch(TBranch *b, Bool_t subgbranches = kFALSE);
156 virtual void LearnPrefill();
157
158 virtual void Print(Option_t *option="") const;
159 virtual Int_t ReadBuffer(char *buf, Long64_t pos, Int_t len);
160 virtual Int_t ReadBufferNormal(char *buf, Long64_t pos, Int_t len);
161 virtual Int_t ReadBufferPrefetch(char *buf, Long64_t pos, Int_t len);
162 virtual void ResetCache();
163 void ResetMissCache(); // Reset the miss cache.
165 virtual Int_t SetBufferSize(Int_t buffersize);
166 virtual void SetEntryRange(Long64_t emin, Long64_t emax);
169 static void SetLearnEntries(Int_t n = 10);
170 void SetOptimizeMisses(Bool_t opt);
171 void StartLearningPhase();
172 virtual void StopLearningPhase();
173 virtual void UpdateBranches(TTree *tree);
174
175 ClassDef(TTreeCache,3) //Specialization of TFileCacheRead for a TTree
176};
177
178#endif
#define b(i)
Definition: RSha256.hxx:100
int Int_t
Definition: RtypesCore.h:45
const Bool_t kFALSE
Definition: RtypesCore.h:101
bool Bool_t
Definition: RtypesCore.h:63
double Double_t
Definition: RtypesCore.h:59
long long Long64_t
Definition: RtypesCore.h:80
unsigned long long ULong64_t
Definition: RtypesCore.h:81
const Bool_t kTRUE
Definition: RtypesCore.h:100
const char Option_t
Definition: RtypesCore.h:66
#define ClassDef(name, id)
Definition: Rtypes.h:325
int type
Definition: TGX11.cxx:121
A TTree is a list of TBranches.
Definition: TBranch.h:89
A cache when reading files over the network.
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition: TFile.h:54
ECacheAction
TTreeCache flushing semantics.
Definition: TFile.h:71
@ kDisconnect
Definition: TFile.h:71
A doubly linked list.
Definition: TList.h:44
An array of TObjects.
Definition: TObjArray.h:37
A cache to speed-up the reading of ROOT datasets.
Definition: TTreeCache.h:32
Bool_t fAutoCreated
! true if cache was automatically created
Definition: TTreeCache.h:66
virtual Int_t AddBranch(TBranch *b, Bool_t subgbranches=kFALSE)
Add a branch to the list of branches to be stored in the cache this function is called by the user vi...
Definition: TTreeCache.cxx:374
virtual void SetLearnPrefill(EPrefillType type=kNoPrefill)
Set whether the learning period is started with a prefilling of the cache and which type of prefillin...
virtual void UpdateBranches(TTree *tree)
Update pointer to current Tree and recompute pointers to the branches in the cache.
void SetOptimizeMisses(Bool_t opt)
Start of methods for the miss cache.
Definition: TTreeCache.cxx:681
Double_t GetEfficiencyRel() const
This will indicate a sort of relative efficiency... a ratio of the reads found in the cache to the nu...
Bool_t fReverseRead
! reading in reverse mode
Definition: TTreeCache.h:58
Bool_t fLearnPrefilling
! true if we are in the process of executing LearnPrefill
Definition: TTreeCache.h:68
Long64_t fLastMiss
! set to the event # of the last miss.
Definition: TTreeCache.h:74
Int_t fNMissReadPref
Number of blocks read into the secondary ("miss") cache.
Definition: TTreeCache.h:50
virtual Int_t SetBufferSize(Int_t buffersize)
Change the underlying buffer size of the cache.
Int_t fNMissReadOk
Number of blocks read, not found in the primary cache, and found in the secondary cache.
Definition: TTreeCache.h:46
Bool_t fOneTime
! used in the learning phase
Definition: TTreeCache.h:57
virtual EPrefillType GetLearnPrefill() const
Definition: TTreeCache.h:146
virtual void SetFile(TFile *file, TFile::ECacheAction action=TFile::kDisconnect)
Change the file that is being cached.
Long64_t fEntryMin
! first entry in the cache
Definition: TTreeCache.h:38
virtual Bool_t FillBuffer()
Fill the cache buffer with the branches in the cache.
Bool_t ProcessMiss(Long64_t pos, int len)
! Given a file read not in the miss cache, handle (possibly) loading the data.
Definition: TTreeCache.cxx:861
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 1...
TTreeCache(const TTreeCache &)=delete
this class cannot be copied
Bool_t CalculateMissCache()
Calculate the appropriate miss cache to fetch; helper function for FillMissCache.
Long64_t fEntryNext
! next entry number where cache must be filled
Definition: TTreeCache.h:41
Int_t fNReadMiss
Number of blocks read and not found in the cache.
Definition: TTreeCache.h:47
Double_t GetEfficiency() const
Give the total efficiency of the primary cache... defined as the ratio of blocks found in the cache v...
Bool_t fEnabled
! cache enabled for cached reading
Definition: TTreeCache.h:63
Bool_t fIsLearning
! true if cache is in learning mode
Definition: TTreeCache.h:54
TTree * GetTree() const
Definition: TTreeCache.h:149
Long64_t fNextClusterStart
! End+1 of the cluster(s) where the current content was picked out
Definition: TTreeCache.h:43
const TObjArray * GetCachedBranches() const
Definition: TTreeCache.h:139
virtual ~TTreeCache()
Destructor. (in general called by the TFile destructor)
Definition: TTreeCache.cxx:330
Bool_t CheckMissCache(char *buf, Long64_t pos, int len)
Check the miss cache for a particular buffer, fetching if deemed necessary.
Definition: TTreeCache.cxx:919
Int_t fNMissReadMiss
Number of blocks read and not found in either cache.
Definition: TTreeCache.h:48
IOPos FindBranchBasketPos(TBranch &, Long64_t entry)
Given a branch and an entry, determine the file location (offset / size) of the corresponding basket.
Definition: TTreeCache.cxx:714
virtual void SetEntryRange(Long64_t emin, Long64_t emax)
Set the minimum and maximum entry number to be processed this information helps to optimize the numbe...
TTreeCache()
Default Constructor.
Definition: TTreeCache.cxx:311
std::unique_ptr< MissCache > fMissCache
! Cache contents for misses
Definition: TTreeCache.h:105
@ kAllBranches
Definition: TTreeCache.h:35
Bool_t fFirstTime
! save the fact that we processes the first entry
Definition: TTreeCache.h:60
void StartLearningPhase()
The name should be enough to explain the method.
virtual Int_t LearnBranch(TBranch *b, Bool_t subgbranches=kFALSE)
Add a branch discovered by actual usage to the list of branches to be stored in the cache this functi...
Definition: TTreeCache.cxx:348
Bool_t IsAutoCreated() const
Definition: TTreeCache.h:150
virtual Bool_t IsLearning() const
Definition: TTreeCache.h:152
Bool_t fReadDirectionSet
! read direction established
Definition: TTreeCache.h:62
TBranch * CalculateMissEntries(Long64_t, int, bool)
Given an file read, try to determine the corresponding branch.
Definition: TTreeCache.cxx:788
Long64_t fCurrentClusterStart
! Start of the cluster(s) where the current content was picked out
Definition: TTreeCache.h:42
Double_t GetMissEfficiency() const
The total efficiency of the 'miss cache' - defined as the ratio of blocks found in the cache versus t...
virtual void Disable()
Definition: TTreeCache.h:136
virtual Int_t ReadBufferNormal(char *buf, Long64_t pos, Int_t len)
Old method ReadBuffer before the addition of the prefetch mechanism.
virtual void ResetCache()
This will simply clear the cache.
Bool_t FillMissCache()
Fill the miss cache from the current set of active branches.
void SetAutoCreated(Bool_t val)
Definition: TTreeCache.h:164
Bool_t fIsManual
! true if cache is StopLearningPhase was used
Definition: TTreeCache.h:55
EPrefillType fPrefillType
Whether a pre-filling is enabled (and if applicable which type)
Definition: TTreeCache.h:64
virtual void LearnPrefill()
Perform an initial prefetch, attempting to read as much of the learning phase baskets for all branche...
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.
Long64_t fEntryMax
! last entry in the cache
Definition: TTreeCache.h:39
Bool_t GetOptimizeMisses() const
Definition: TTreeCache.h:138
static Int_t fgLearnEntries
number of entries used for learning mode
Definition: TTreeCache.h:65
virtual Int_t GetEntryMax() const
Definition: TTreeCache.h:144
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:...
Definition: TTreeCache.cxx:539
virtual Int_t ReadBufferPrefetch(char *buf, Long64_t pos, Int_t len)
Used to read a chunk from a block previously fetched.
Long64_t fEntryCurrent
! current lowest entry number in the cache
Definition: TTreeCache.h:40
void ResetMissCache()
Reset all the miss cache training.
Definition: TTreeCache.cxx:695
Long64_t fFirstMiss
! set to the event # of the first miss.
Definition: TTreeCache.h:73
virtual Int_t GetEntryMin() const
Definition: TTreeCache.h:143
Double_t GetMissEfficiencyRel() const
Relative efficiency of the 'miss cache' - ratio of the reads found in cache to the number of reads so...
Long64_t fFirstEntry
! save the value of the first entry
Definition: TTreeCache.h:61
Int_t fFillTimes
! how many times we can fill the current buffer
Definition: TTreeCache.h:59
Int_t fNReadPref
Number of blocks that were prefetched.
Definition: TTreeCache.h:49
TTree * fTree
! pointer to the current Tree
Definition: TTreeCache.h:53
EPrefillType GetConfiguredPrefillType() const
Return the desired prefill type from the environment or resource variable.
TTreeCache & operator=(const TTreeCache &)=delete
Bool_t fFirstBuffer
! true if first buffer is used for prefetching
Definition: TTreeCache.h:56
static Int_t GetLearnEntries()
Static function returning the number of entries used to train the cache see SetLearnEntries.
virtual void StopLearningPhase()
This is the counterpart of StartLearningPhase() and can be used to stop the learning phase.
Bool_t fOptimizeMisses
! true if we should optimize cache misses.
Definition: TTreeCache.h:72
virtual void Enable()
Definition: TTreeCache.h:137
Int_t fNbranches
! Number of branches in the cache
Definition: TTreeCache.h:44
virtual Bool_t IsEnabled() const
Definition: TTreeCache.h:151
Int_t fNReadOk
Number of blocks read and found in the cache.
Definition: TTreeCache.h:45
virtual void Print(Option_t *option="") const
Print cache statistics.
TObjArray * fBranches
! List of branches to be stored in the cache
Definition: TTreeCache.h:51
TList * fBrNames
! list of branch names in the cache
Definition: TTreeCache.h:52
A TTree represents a columnar dataset.
Definition: TTree.h:79
const Int_t n
Definition: legend1.C:16
Definition: file.py:1
Definition: tree.py:1
Int_t fLen
Position in file of cache entry.
Definition: TTreeCache.h:82
IOPos(Long64_t pos, Int_t len)
Definition: TTreeCache.h:79
ULong64_t fIndex
! Location in fData corresponding to this entry.
Definition: TTreeCache.h:90
friend bool operator<(const Entry &a, const Entry &b)
Definition: TTreeCache.h:91
std::vector< Entry > fEntries
! Description of buffers in the miss cache.
Definition: TTreeCache.h:93
std::vector< char > fData
! Actual data in the cache.
Definition: TTreeCache.h:95
std::vector< TBranch * > fBranches
! list of branches that we read on misses.
Definition: TTreeCache.h:94
auto * a
Definition: textangle.C:12