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Open Trace Format (OTF) Tutorial

Open Trace Format (OTF) Tutorial. Wolfgang E. Nagel, Holger Brunst, T.U. Dresden, Germany Sameer Shende, Allen D. Malony, ParaTools, Inc. http://www.vampir.eu otf@paratools.com. Outline. An overview of OTF, TAU and Vampir/VNG OTF Tools API Building trace conversion tools TAU

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Open Trace Format (OTF) Tutorial

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  1. Open Trace Format (OTF) Tutorial Wolfgang E. Nagel, Holger Brunst, T.U. Dresden, Germany Sameer Shende, Allen D. Malony, ParaTools, Inc. http://www.vampir.eu otf@paratools.com

  2. Outline • An overview of OTF, TAU and Vampir/VNG • OTF • Tools • API • Building trace conversion tools • TAU • Instrumentation • Measurement • Analysis • Scalable Tracing • Vampir • VNG • OTF

  3. Tutorial Goals • This tutorial is intended as an introduction to OTF tools. • Today you should leave here with a better understanding of… • OTF API and tools • Steps involved in building a trace conversion tool to target OTF • How to instrument your programs with TAU to generate OTF • Automatic instrumentation at the routine level and outer loop level • Manual instrumentation at the loop/statement level • Measurement options provided by TAU • Environment variables used for choosing metrics, generating performance data • How to use the Vampir and VNG tools • Nature and types of visualization that VNG provides for visualizing OTF traces

  4. Server Trace 1 Trace 2 Trace 3 Worker 1 Trace N Master Worker 2 Worker m Vampir: Technical Components Tools • Trace generator • Classical Vampir viewer and analyzer • Vampir client viewer • Parallel server engine • Conversion and analysis tools

  5. Many Trace Formats to choose from …

  6. OTF Features • Fast and efficient sequential and parallel access • Platform independent • Selective access to • Processes • Time intervals • API / Interfaces • High level interface for analysis tools • Read/write complete traces with multiple files • Supports filtering and parallel I/O • Low level interface for trace libraries

  7. Relative File Size Better

  8. Read Performance Better

  9. Performance Scalability Better

  10. Parallel Program File System Analysis Server MergedTraces Worker 1 Master Classic Analysis: • monolithic • sequential Trace 1 Worker 2 Trace 2 Trace 3 Trace N Worker m Internet Visualization Client Vampir Server Workflow Monitor System (TAU/Kojak) Event Streams Message Passing ParallelI/O Process Timeline with 16 visible Traces Segment Indicator 768 Processes Thumbnail

  11. Worker Master Message Passing Message Passing Worker 1 Master Session Thread Session Thread Worker 2 Analysis Module Analysis Merger Worker m Visualization Client Event Databases Endian Conversion Traces Trace Format Driver Socket Communication N Session Threads N Session Threads M Worker Organization of Parallel Analysis

  12. Scalability – sPPM Analyzed on Origin 2000 • sPPM ASCI Benchmark • 3D Gas Dynamic • Data to be analyzed • 16 Processes • 200 MByte Volume

  13. A Fairly Large Test Case • IRS ASCI Benchmark • Implicit Radiation Solver • Data to be analyzed: • 64 Processes in8 Streams • Approx.800.000.000 Events • 40 GByte Data Volume • Analysis Platform: • Jump.fz-juelich.de • 41 IBM p690 nodes (32 processors per node) • 128 GByte per node • Visualization Platform: • Remote Laptop

  14. Outline • An overview of OTF, TAU and Vampir/VNG • OTF • Tools • API • Building trace conversion tools • TAU • Instrumentation • Measurement • Analysis • Scalable Tracing • Vampir • VNG • OTF

  15. OTF Trace Generation and Analysis Tools

  16. OTF Contents • Definition records • Map event ids to interval (begin/end) event names • Symbols for atomic events • Process groups • Performance events • Timestamped events for entering or leaving a state • Timestamped counter events (monotonically increasing or not) • Global master file • Mapping processes to streams • Statistical Summaries • Overview over a whole interval of time • Snapshots • Callstack, list of pending messages, etc. at a point in time

  17. OTF File Hierarchy

  18. OTF Streams

  19. otfmerge • Allows an existing OTF trace to alter the number of streams • Add snapshots or statistics to the merged trace file • otfmerge - converter program of OTF library. otfmerge [Options] <input file name> options: -h, --help show this help message -n <n> set number of streams for output -f <n> set max number of filehandles available -o <name> namestub of the output file (default ’out’) -rb <size> set buffersize of the reader -wb <size> set buffersize of the writer -stats cover statistics too -snaps cover snapshots too -V show OTF version

  20. OTF Tools: otfaux • otfaux • Adds auxillary snapshot and/or statistics information to the trace file • Snapshots include callstack, pending messages, current counter values • Statistics include number of calls, exclusive/inclusive time • Statistics are monotonically increasing - unlike profiles • Original event trace is unmodified • Auxillary data is generated at breakpoints -periodically or at ticks

  21. otfaux • otfaux - append snapshots and statistics to existing otf traces at given ’break’ time stamps otfaux [Options] <file name> Options: -h, --help show this help message -b <size> buffer size for read and write operations -n <n> number of breaks (distributed regularly) if -p and -t are not set, the default for -n is 200 breaks -p <p> create break every ’p’ ticks (if both, -n and -p are specified the one producing more breaks wins) -t <t> define (additional) break at given time stamp -F force overwrite old snapshots and statistics -R delete existing snapshots and statistics only -f <n> max number of filehandles output ...

  22. otfaux (contd.) -g create functiongroup summaries instead of function summaries -v verbose mode, print break time stamps -V show OTF version -a show advancing progress during operation -- snapshots write ONLY snapshots but NO statistics --statistics write ONLY statistics but NO snapshots -s a[,b]* regard given streams only when computing statistics. expects a single token or comma separated list. this implies the ’--statistics’ option! -l list existing stream tokens

  23. tau2otf • Converts TAU traces to OTF • tau2otf <TAU trace> <edf file> <out file> [-n streams] [-nomessage] [-z] [-v] -n <streams> : Specifies the number of output streams (default 1) -nomessage : Suppress printing of message information in the trace -z : Enable compression of trace files. By default it is uncompressed. -v : Verbose Trace format of <out file> is OTF % tau2otf merged.trc tau.edf app.otf

  24. vtf2otf • Convert VTF traces to OTF format • vtf2otf [Options] <input file name> Options: -o <file> output file -f <n> max count of filehandles -n <n> output stream count -b <n> size of the writer buffer -V show OTF version

  25. otf2vtf • Convert OTF trace files to VTF format • otf2vtf [Options] <input file name> Options: -o <file> output file -b <n> size of the reader buffer -A write VTF3 ASCII sub-format (default) -B write VTF3 binary sub-format -V show OTF version

  26. Building Trace Analysis Tools • Writing OTF traces in trace conversion tools • High level API writes multiple streams • Low level API writes a single stream • Each OTF file has a prefix (e.g., app.otf) • Parallel reading and searching in OTF analysis tools • Each process in tool reads local and global event definitions • Each process reads a subset of events • Read summary information to select interesting spots in trace • Tool might read a selected time interval for analysis • OTF supports efficient binary search • Tool may support for compressed or uncompressed OTF trace • Tool may support for single or multi-stream OTF traces

  27. OTF Trace Writer API - OTF_FileManager_open • Generates a new file manager with a maximum number of files that are allowed to be open simultaneously • OTF_FileManager* OTF_FileManager_open( uint32_t number ); #include <otf.h> OTF_FileManager *manager; manager = OTF_FileManager_open(256);

  28. OTF_FileManager_close • Closes the file manager • void OTF_FileManager_close( OTF_FileManager* m ); #include <otf.h> OTF_FileManager_close(manager);

  29. OTF_Writer_open • Define file control block for output trace file • OTF_Writer* OTF_Writer_open( char* fileNamePrefix, uint32_t numberOfStreams, OTF_FileManager* fileManager ); #include <otf.h> void *fcb = (void *) OTF_Writer_open(out_file, num_streams, manager);

  30. OTF_Writer_setCompression • Enable compression if specified by the user • int OTF_Writer_setCompression( OTF_Writer* writer, OTF_FileCompression); #include <otf.h> OTF_Writer_setCompression((OTF_Writer *)fcb, OTF_FILECOMPRESSION_COMPRESSED);

  31. OTF_Writer_writeDefCreator • Specify a comment about the creator (trace conversion tool) • int OTF_Writer_writeDefCreator( void* userData, uint32_t stream, /* stream = 0 means global definition */ const char* creator ); #include <otf.h> OTF_Writer_writeDefCreator(fcb, 0, “MyTool2otf ver 2.42”);

  32. OTF_Writer_writeDefProcess • Write a process definition record • int OTF_Writer_writeDefProcess( OTF_Writer* writer, uint32_t stream, uint32_t process, const char* name, uint32_t parent ); #include <otf.h> OTF_Writer_writeDefProcess( (OTF_Writer *)fcb, 0, cpuid, name, 0);

  33. OTF_Writer_writeDefTimerResolution • Provides the timer resolution. All timestamps are interpreted based on this resolution. By default it is 1 microseconds. • int OTF_Writer_write_DefTimerResolution( void* userData, uint32_t stream, uint64_t ticksPerSecond ); #include <otf.h> OTF_Writer_writeDefTimerResolution((OTF_Writer*) userData, 0, getTicksPerSecond());

  34. OTF_Writer_write_DefFunction • Provide a function definition and specify an event id to name mapping • int OTF_Writer_write_DefFunction( void* userData, uint32_t stream, uint32_t func, const char* name, uint32_t funcGroup, uint32_t source ); /* specify source code location */ #include <otf.h> OTF_Writer_writeDefFunction((OTF_Writer*)userData, 0, eventID, (const char *) name, groupID, 0);

  35. OTF_Writer_writeDefFunctionGroup • Provides a function group definition • int OTF_Handler_DefFunctionGroup( void* userData, uint32_t stream, uint32_t funcGroup, const char* name ); #include <otf.h>OTF_Writer_writeDefFunctionGroup((OTF_Writer*)userData, 0, groupId, GroupName);

  36. OTF_Writer_writeEnter • Write a function entry record • int OTF_Writer_writeEnter( OTF_Writer* writer, uint64_t time, uint32_t function, uint32_t process, uint32_t source ); #include <otf.h> OTF_Writer_writeEnter((OTF_Writer*)userData, GetClockTicksInGHz(time), stateid, cpuid, 0);

  37. int OTF_Writer_writeSendMsg • Write a send message record • int OTF_Writer_writeSendMsg( OTF_Writer* writer, uint64_t time, uint32_t sender, uint32_t receiver, uint32_t procGroup, uint32_t tag, uint32_t length, uint32_t source );

  38. int OTF_Writer_writeRecvMsg • Write a receive message record • int OTF_Writer_writeRecvMsg( OTF_Writer* writer, uint64_t time, uint32_t receiver, uint32_t sender, uint32_t procGroup, uint32_t tag, uint32_t length, uint32_t source );

  39. OTF Trace Reader API • Similar to trace writer API • Instead of Write, create a Handler for callbacks, e.g., • int OTF_Handler_DefFunction( void* userData, uint32_t stream, uint32_t func, const char* name, uint32_t funcGroup, uint32_t source );

  40. OTF Trace Reader API • Similar to trace writer API • Instead of Write, create a Handler for callbacks • Specify the parameters to the handler routine • After setting up handlers, read events, snapshots, definitions.... The library invokes appropriate handlers • Close the file manager and exit cleanly

  41. Global Read Operations • Open array handler • Open OTF reader • Control the buffer size • Set handler and arguments • Read definitions • Read snapshots • Read events • Close reader

  42. OTF_HandlerArray_open/close • To open a new array of handlers and then fill in the callback routines • OTF_HandlerArray *OTF_HandlerArray_open( void); #include <otf.h> OTF_HandlerArray *handlers; handlers = OTF_HandlerArray_open(); • To close the array, use OTF_HandlerArray_close OTF_HandlerArray_close(handlers);

  43. A Sample Handler • int OTF_handleDefinitionComment( void* fcb, uint32_t streamid, const char* comment ) { /* written by user; called by OTF */ } • The first argument is a file control block. We need to pass this argument and the callback function’s address to the OTF reader.

  44. OTF_HandlerArray_setHandler • int OTFHandlerArray_setHandler( OTF_HandlerArray *handlers, OTFFunctionPointer *pointer, uint32_t recordtype); • int OTF_HandlerArray_setFirstHandlerArg( OTF_HandlerArray* handlers, void* firsthandlerarg, uint32_t recordtype ); • To specify any user defined pointer that should be passed as the first argument. Useful for keeping track of location.

  45. OTF_HandlerArray_setHandler #include <otf.h> OTF_HandlerArray *handlers = OTF_HandlerArray_Open(); ... /* put the callback routine’s address in the array */ OTF_HandlerArray_setHandler( handlers, (OTF_FunctionPointer*) OTF_handleDefinitionComment, OTF_DEFINITIONCOMMENT_RECORD ); /* specify the file position/any address (of say the trace writer) as the first argument*/ OTF_HandlerArray_setFirstHandlerArg( handlers, &fcb, OTF_DEFINITIONCOMMENT_RECORD ); /* invokes OTF_handleDefinitionComment routine*/

  46. OTF_Reader_open • Opens a master control file and returns an OTF_Reader • OTF_Reader * OTF_Reader_open(char *name, OTF_FileManager *manager); #include <otf.h> OTF_FileManager *manager = OTF_FileManager_open(256); OTF_Reader *reader = OTF_Reader_open(“inputfile”, manager);

  47. User defined handlers for definitions • int handleDeftimerresolution( void* firsthandlerarg, uint32_t streamid, uint64_t ticksPerSecond ) { ...} • int handleDefprocess( void* firsthandlerarg, uint32_t streamid, uint32_t deftoken, const char* name, uint32_t parent) { ... } • int handleDefprocessgroup( void* firsthandlerarg, uint32_t streamid, uint32_t deftoken, const char* name, uint32_t n, uint32_t* array ) { } • int handleDeffunction( void* firsthandlerarg, uint32_t streamid, uint32_t deftoken, const char* name, uint32_t group, uint32_t scltoken ) { } • int handleDefcounter( void* firsthandlerarg, uint32_t streamid, uint32_t deftoken, const char* name, uint32_t properties, uint32_t countergroup, const char* unit ) { } ...

  48. User defined handlers for timestamped events • int handleCounter( void* firsthandlerarg, uint64_t time, uint32_t process, uint32_t token, uint64_t value ) {... } • int handleRecvmsg( void* firsthandlerarg, uint64_t time, uint32_t receiver, uint32_t sender, uint32_t communicator, uint32_t msgtype, uint32_t msglength, uint32_t scltoken ) • int handleSendmsg( void* firsthandlerarg, uint64_t time, uint32_t sender, uint32_t receiver, uint32_t communicator, uint32_t msgtype, uint32_t msglength, uint32_t scltoken ) • int handleEnter( void* firsthandlerarg, uint64_t time, uint32_t statetoken, uint32_t cpuid, uint32_t scltoken ) {...} • int handleLeave( void* firsthandlerarg, uint64_t time, uint32_t statetoken, uint32_t cpuid, uint32_t scltoken ) {...}

  49. OTF_Reader_readDefinitions • int OTF_Reader_readDefinitions(OTF_Reader *r, OTF_HandlerArray *handlers); #include <otf.h> OTF_HandlerArray *handlers = OTF_HandlerArray_open(); OTF_Manager *manager = OTF_FileManager_open(100); OTF_Reader *reader = OTF_Reader_open(inputFile, manager); /* set up handlers */ OTF_Reader_readDefinitions(reader, handlers); /* OTF invokes handlers for process, functions, groups and counters here */

  50. OTF_Reader_readEvents • int OTF_Reader_readEvents(OTF_Reader *reader, OTF_HandlerArray *handlers); #include <otf.h> OTF_Reader_readEvents (reader, handlers); /* invokes handlers for timestamped message communication, routine entry/exit, counter events */

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