Intel® Trace Analyzer and Collector User and Reference Guide

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ID 767272
Date 10/31/2024
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Document Table of Contents
Document Table of Contents x
Intel® Trace Analyzer and Collector User and Reference Guide
Intel® Trace Analyzer and Collector User and Reference Guide x
Introduction Install and Set Up Intel® Trace Analyzer and Collector Trace Your Applications Analyze Your Applications Intel® Trace Collector Reference Intel® Trace Analyzer Reference Notices and Disclaimers
Introduction x
Notational Conventions Get Help
Trace Your Applications x
Tracing Conventional MPI Applications Tracing Failing MPI Applications Tracing OpenSHMEM* Applications Tracing MPI File IO Handling of Communicator Names Tracing MPI Load Imbalance Tracing User Defined Events Configuring the Collector Filtering Trace Data Recording OpenMP* Regions Information Tracing System Calls (Linux* OS) Collecting Lightweight Statistics Recording Source Location Information Recording Hardware Performance Information (Linux* OS) Recording Operating System Counters Tracing Library Calls Correctness Checking Tracing Distributed Non-MPI Applications
Correctness Checking x
Correctness Checking of MPI Applications Running with Valgrind* (Linux* OS) Configuring Error Checks Analyzing the Results Debugger Integration
Debugger Integration x
TotalView* Debugger GNU* Symbolic Debugger Allinea* Distributed Debugging Tool* (DDT*)
Analyze Your Applications x
Starting Intel® Trace Analyzer Intel Trace Analyzer Graphical User Interface Navigating Timelines Concepts Viewing Correctness Checking Reports Comparing Two Trace Files Interoperability with Intel® VTune™ Profiler and Intel® Advisor OpenMP* Regions Display Support OTF2 Format Support
Navigating Timelines x
Zoom Stack
Concepts x
Level of Detail Aggregation Advanced Aggregation Tagging and Filtering
Viewing Correctness Checking Reports x
Event Timeline Correctness Checking Reports Qualitative Timeline Correctness Checking Reports Detailed Dialog
Comparing Two Trace Files x
Mappings in Comparison Views Comparison Charts
Mappings in Comparison Views x
Mapping of Processes Mapping of Functions
Comparison Charts x
Comparison Function Profile Comparison Message Profile Comparison Collective Operations Profile
Intel® Trace Collector Reference x
API Reference Configuration Reference Correctness Checking Errors Structured Tracefile Format stftool Utility Time Stamping Secure Loading of Dynamic Link Libraries* on Windows* OS
API Reference x
Initialization, Termination and Control Defining and Recording Source Locations Defining and Recording Functions or Regions Defining and Recording Scopes Defining Groups of Processes Defining and Recording Counters Recording Communication Events Additional API Calls in libVTcs C++ API
Initialization, Termination and Control x
VT_initialize VT_finalize VT_getrank VT_registerthread VT_registernamed VT_registerprefixed VT_getthrank VT_traceon VT_traceoff VT_tracestate VT_symstate VT_flush VT_timestamp VT_timestart VT_setfinalizecallback VT_getdescription VT_countsetcallback
Defining and Recording Functions or Regions x
New Interface Old Interface State Changes
C++ API x
VT_FuncDef Class Reference VT_SclDef Class Reference VT_Function Class Reference VT_Region Class Reference
Configuration Reference x
Configuration File Format Protocol File Configuration Options
Configuration Options x
ACTIVITY ALTSTACK AUTOFLUSH CHECK CHECK-LEAK-REPORT-SIZE CHECK-MAX-DATATYPES CHECK-MAX-ERRORS CHECK-MAX-PENDING CHECK-MAX-REPORTS CHECK-MAX-REQUESTS CHECK-SUPPRESSION-LIMIT CHECK-TIMEOUT CHECK-TRACING CLUSTER COMPRESS-RAW-DATA COUNTER CURRENT-DIR DEADLOCK-TIMEOUT DEADLOCK-WARNING DEMANGLE DETAILED-STATES ENTER-USERCODE ENVIRONMENT EXTENDED-VTF FLUSH-PID FLUSH-PREFIX GROUP HANDLE-SIGNALS INTERNAL-MPI KEEP-RAW-EVENTS LOGFILE-FORMAT LOGFILE-NAME LOGFILE-PREFIX LOGFILE-RANK MEM-BLOCKSIZE MEM-FLUSHBLOCKS MEM-INFO MEM-MAXBLOCKS MEM-MINBLOCKS MEM-OVERWRITE NMCMD OS-COUNTER-DELAY PCTRACE PCTRACE-CACHE PCTRACE-FAST PLUGIN PROCESS PROGNAME PROTOFILE-NAME STATISTICS STATE STF-PROCS-PER-FILE STF-USE-HW-STRUCTURE STOPFILE-NAME SYMBOL SYNC-MAX-DURATION SYNC-MAX-MESSAGES SYNC-PERIOD SYNCED-CLUSTER SYNCED-HOST TIME-WINDOWS (Experimental) TIMER TIMER-SKIP UNIFY-COUNTERS UNIFY-GROUPS UNIFY-SCLS UNIFY-SYMBOLS VERBOSE VT_START_PAUSED VT_COMPRESS_TRACE
Correctness Checking Errors x
Supported Errors How the Collection Works
How the Collection Works x
Parameter Checking Premature Exit Overlapping Memory Detecting Illegal Buffer Modifications Buffer Given to MPI Cannot Be Read or Written Distributed Memory Checking Illegal Memory Access Request Handling Datatype Handling Buffered Sends Deadlocks Checking Message Transmission Datatype Mismatches Data Modified during Transmission Checking Collective Operations Freeing Communicators
Structured Tracefile Format x
STF Components Single-File STF Configuring STF
stftool Utility x
stftool Utility Options Expanded ASCII output of STF Files
Time Stamping x
Clock Synchronization Choosing a Timer
Choosing a Timer x
gettimeofday/_ftime QueryPerformanceCounter CPU Cycle Counter Normalized CPU Cycle Counter MPI_Wtime() High Precision Event Timers POSIX* clock_gettime
Intel® Trace Analyzer Reference x
Graphical User Interface Reference Intel® Trace Analyzer Command Line Interface Reference Filter Expression Grammar otf2-to-stf Utility
Graphical User Interface Reference x
Welcome Page Summary Page Main Menu Bar View Menu Bar View Bars Charts Dialogs Settings
Main Menu Bar x
File Menu Options Menu Project Menu  Windows Menu Help Menu
View Menu Bar x
View Charts Navigate Advanced Layout Comparison Menu
Advanced x
Tagging Specific Events Filtering Events Simulating Ideal Communication Checking Application Imbalance Aggregating Results Aggregating Functions Creating Command Line for Intel® VTune™ Profiler and Intel® Advisor
View Bars x
Toolbar Trace Map Status Bar
Charts x
Event Timeline Qualitative Timeline Quantitative Timeline Counter Timeline Function Profile Message Profile Collective Operations Profile Performance Assistant Common Chart Features
Event Timeline x
Context Menu Filtering and Tagging
Qualitative Timeline x
Context Menu Filtering and Tagging
Quantitative Timeline x
Context Menu Filtering and Tagging
Counter Timeline x
Context Menu Filtering and Tagging
Function Profile x
Flat Profile Load Balance Call Tree Call Graph Context Menu Filtering and Tagging Function Profile Settings
Message Profile x
Context Menu Filtering and Tagging Aggregation Message Profile Settings
Collective Operations Profile x
Context Menu Filtering and Tagging Collective Operations Profile Settings
Dialogs x
Process Aggregation Function Aggregation Function Group Color Editor Filtering Dialog Box Tagging Dialog Box Idealization Dialog Box Imbalance Diagram Dialog Box Trace Merge Dialog Box  Details Dialog Box Source View Dialog Time Interval Selection Configuration Dialogs Find Dialog Box Command line for Intel® VTune™ Profiler and Intel® Advisor Dialog Box OTF2 to STF Conversion Dialog Box Configuration Assistant
Process Aggregation x
Comparison Mode
Function Aggregation x
Comparison Mode
Filtering Dialog Box x
Building Filter Expressions Using Graphical Interface Building Filter Expressions Manually Filter Expressions in Comparison Mode
Details Dialog Box x
Detailed Attributes of Function Events Detailed Attributes of Message Events Detailed Attributes of Collective Operation Events
Configuration Dialogs x
Load Configuration File Dialog Edit Configuration File Dialog
Settings x
Preferences Font Settings Number Formatting Settings
Preferences x
General Preferences Tracefile Preferences Event Timeline Settings Qualitative Timeline Settings Quantitative Timeline Settings Counter Timeline Settings
Notices and Disclaimers x
Appendix A Copyright and Licenses
Intel® Trace Analyzer and Collector User and Reference Guide

Level of Detail

Tracing all available events over time can generate billions of events even for a moderate program runtime of a few minutes and a handful of CPUs. The sheer amount of data is a challenge for any analysis tool that has to cope with this data. This is even worse as in most cases the analysis tool cannot make use of the same system resources as the parallel computer on which the trace was generated.

An aspect of this problem arises when generating graphical diagrams of the event data. Obviously, it is next to impossible to graphically display all the data. Firstly, it would take ages to do that. Secondly, it would depend on round-off errors in the scaling and on the order of the data traversal which events would actually make it to the screen without being erased by others. So it is clear that only representatives of the actual events are shown.

A valid choice would be to paint only every 100th or 1000th event and to hope that the resulting diagram gives a valid impression of the data. But this approach has its problems, because the pattern selects the representatives can interfere with the patterns in the underlying data.

Intel® Trace Analyzer uses a Level of Detail concept to solve this problem. The Event Timeline Chart (as the other timelines) calculates a hint for the analysis that describes a time span that can reasonably be painted and selected with the mouse. This hint is called Resolution. The resolution requested by the timeline takes into account the currently available screen space and the length of the current time interval. Hence a higher screen resolution or a wider timeline results in more data being displayed for the same time interval.

Intel® Trace Analyzer then tries to find a near match for the requested resolution. The exact resolution depends on internals, which will not be discussed here.

Intel Trace Analyzer divides the requested time interval into slots of length resolution. After that, representatives for the function events, the messages and the collectives in these slots are chosen in a deterministic way. If a functions spans more than the given resolution it results in a larger slot.

The representatives for function events are chosen as follows: for each slot and each process (or thread group respectively) there is only a single function event representing the function where the thread or group spent most of its time.

The representatives for messages are chosen as follows: for each tuple (sender, receiver, sender slot, receiver slot) only one message is generated that carries averaged attributes. These attributes are averaged over all messages matching the tuple.

The representatives for collective operations are chosen as follows: for each tuple (communicator, first slot) one collective operation is generated. So it can happen that an operation of type MPI_Gather is merged with an operation of type MPI_Bcast resulting in a merged operation with no particular type at all (mixed).

To prevent misconceptions, emphasis is given to the fact that the merging of events only applies to the timelines and not to the profiles. The profiles always show sums, minima, maxima or averages over the complete set of events. The calculation of these results does obviously not depend on the screen resolution.

Parent topic: Concepts
Level Two Title