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The TAU Performance System is a flexible and scalable performance monitoring and analysis tool for High Performance Computing systems. It provides comprehensive performance profiling, tracing, and data mining capabilities for parallel programs across multiple programming paradigms.
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Performance Technology for Productive, High Performance Computing:the TAU Performance SystemTM Allen D. Malony malony@cs.uoregon.edu http://tau.uoregon.edu Department of Computer and Information Science Performance Research Laboratory University of Oregon
Acknowledgements • Dr. Sameer Shende, Director, Performance Research Lab • Alan Morris, Senior software engineer • Wyatt Spear, Software engineer • Scott Biersdorff, Software engineer • Dr. Matt Sottile, Research Faculty • Kevin Huck, Ph.D. student • Aroon Nataraj, Ph.D. student • Shangkar Mayanglambam, Ph.D. student • Brad Davidson, Systems administrator
TAU Performance System Project • Tuning and Analysis Utilities (15+ year project effort) • Performance system framework for HPC systems • Integrated, scalable, and flexible • Target parallel programming paradigms • Integrated toolkit for performance problem solving • Instrumentation, measurement, analysis, and visualization • Portable performance profiling and tracing facility • Performance data management and data mining • Partners • LLNL, ANL, LANL • Research Centre Jülich, TU Dresden
TAU Parallel Performance System Goals • Portable (open source) parallel performance system • Computer system architectures and operating systems • Different programming languages and compilers • Multi-level, multi-language performance instrumentation • Flexible and configurable performance measurement • Support for multiple parallel programming paradigms • Multi-threading, message passing, mixed-mode, hybrid, object oriented (generic), component-based • Support for performance mapping • Integration of leading performance technology • Scalable (very large) parallel performance analysis
Performance Monitoring TAU Performance System Components Performance Data Mining TAU Architecture Program Analysis PDT PerfExplorer Parallel Profile Analysis PerfDMF ParaProf TAUoverSupermon
TAU Instrumentation Approach • Support for standard program events • Routines, classes and templates • Statement-level blocks • Begin/End events (Interval events) • Support for user-defined events • Begin/End events specified by user • Atomic events (e.g., size of memory allocated/freed) • Selection of event statistics • Support definition of “semantic” entities for mapping • Support for event groups (aggregation, selection) • Instrumentation optimization • Eliminate instrumentation in lightweight routines
TAU Instrumentation Mechanisms • Source code • Manual (TAU API, TAU component API) • Automatic (robust) • C, C++, F77/90/95 (Program Database Toolkit (PDT)) • OpenMP (directive rewriting (Opari), POMP2 spec) • Object code • Pre-instrumented libraries (e.g., MPI using PMPI) • Statically-linked and dynamically-linked • Executable code • Binary and dynamic instrumentation (Dyninst) • Virtual machine instrumentation (e.g., Java using JVMPI) • TAU_COMPILER to automate instrumentation process
User-level abstractions problem domain linker OS Multi-Level Instrumentation and Mapping • Multiple interfaces • Information sharing • Between interfaces • Event selection • Within/between levels • Mapping • Associate performance data with high-level semantic abstractions source code instrumentation preprocessor instrumentation source code instrumentation compiler instrumentation object code libraries executable instrumentation instrumentation runtime image instrumentation instrumentation VM performancedata run
TAU Measurement Approach • Portable and scalable parallel profiling solution • Multiple profiling types and options • Event selection and control (enabling/disabling, throttling) • Online profile access and sampling • Online performance profile overhead compensation • Portable and scalable parallel tracing solution • Trace translation to OTF, EPILOG, Paraver, and SLOG2 • Trace streams (OTF) and hierarchical trace merging • Robust timing and hardware performance support • Multiple counters (hardware, user-defined, system) • Performance measurement for CCA component software
TAU Measurement Mechanisms • Parallel profiling • Function-level, block-level, statement-level • Supports user-defined events and mapping events • TAU parallel profile stored (dumped) during execution • Support for flat, callgraph/callpath, phase profiling • Support for memory profiling (headroom, malloc/leaks) • Support for tracking I/O (wrappers, read/write/print calls) • Tracing • All profile-level events • Inter-process communication events • Inclusion of multiple counter data in traced events
Types of Parallel Performance Profiling • Flatprofiles • Metric (e.g., time) spent in an event (callgraph nodes) • Exclusive/inclusive, # of calls, child calls • Callpath profiles (Calldepth profiles) • Time spent along a calling path (edges in callgraph) • “main=> f1 => f2 => MPI_Send” (event name) • TAU_CALLPATH_DEPTH environment variable • Phase profiles • Flat profiles under a phase (nested phases are allowed) • Default “main” phase • Supports static or dynamic (per-iteration) phases
Performance Analysis and Visualization • Analysis of parallel profile and trace measurement • Parallel profile analysis (ParaProf) • Java-based analysis and visualization tool • Support for large-scale parallel profiles • Performance data management framework (PerfDMF) • Parallel trace analysis • Translation to VTF (V3.0), EPILOG, OTF formats • Integration with Vampir / Vampir Server (TU Dresden) • Profile generation from trace data • Online parallel analysis and visualization • Integration with CUBE browser (KOJAK, UTK, FZJ)
ParaProf Manager Raw files HPMToolkit PerfDMFmanaged (database) Metadata MpiP Application Experiment Trial TAU
ParaProf – Flat Profile (Miranda, BG/L) node, context, thread 8K processors Miranda hydrodynamics Fortran + MPI LLNL Run to 64K
ParaProf – Callpath Profile (Flash) Flash thermonuclear flashes Fortran + MPI Argonne
Comparing Effects of Multi-Core Processors • AORSA2D • Magnetized plasma simulation • Blue is single node / Red is dual core • Cray XT3 (4K cores)
Comparing FLOPS (AORSA2D, Cray XT3) • Blue is dual core / Red is single node
ParaProf – Scalable Histogram View (Miranda) 8k processors 16k processors
ParaProf – Full Profile (Miranda) 16k processors
ParaProf –Full Profile (Matmult, ANL BGP!) 256 processors
ParaProf – 3D Scatterplot (Miranda) • Each pointis a “thread”of execution • A total offour metricsshown inrelation • ParaProf’svisualizationlibrary • JOGL
Visualizing Hybrid Problems (S3D, XT3+XT4) • S3D combustion simulation (DOE SciDAC PERI) ORNL Jaguar* Cray XT3/XT4* 6400 cores
Zoom View of Hybrid Execution (S3D, XT3+XT4) • Gap represents XT3 nodes • MPI_Wait takes less time, other routines take more time
Visualizing Hybrid Execution (S3D, XT3+XT4) • Hybridexecution • Processmetadata isused to mapperformanceto machinetype • Memory speedaccounts forperformancedifference 6400 cores
Better balance across nodes More performance uniformity S3D Run on XT4 Only
Profile Snapshots in ParaProf (Flash) • Profile snapshots are parallel profiles recorded at runtime • Used to highlight profile changes during execution Initialization Checkpointing Finalization
Profile Snapshots in ParaProf (Flash) Filter snapshots (only show main loop iterations)
Profile Snapshots in ParaProf (Flash) Breakdown as a percentage
Snapshot replay in ParaProf (Flash) All windows dynamically update
Profile Snapshots in ParaProf (Flash) Follow progression of various displays through time 3D scatter plot shown below T = 0s T = 11s
Performance Data Management • Need for robust processing and storage of multiple profile performance data sets • Avoid developing independent data management solutions • Waste of resources • Incompatibility among analysis tools • Goals • Foster multi-experiment performance evaluation • Develop a common, reusable foundation of performance data storage, access and sharing • A core module in an analysis system, and/or as a central repository of performance data
PerfDMF Approach • Performance Data Management Framework • Originally designed to address critical TAU requirements • Broader goal is to provide an open, flexible framework to support common data management tasks • Extensible toolkit to promote integration and reuse across available performance tools • Supported profile formats: TAU, CUBE (Kojak), Dynaprof, HPC Toolkit (Rice), HPM Toolkit (IBM), gprof, mpiP, psrun (PerfSuite), Open|SpeedShop, … • Supported DBMS: PostgreSQL, MySQL, Oracle, DB2, Derby/Cloudscape • Profile query and analysis API
K. Huck, A. Malony, R. Bell, A. Morris, “Design and Implementation of a Parallel Performance Data Management Framework,” ICPP 2005. PerfDMF Architecture
Metadata Collection • Integration of XML metadata for each profile • Three ways to incorporate metadata • Measured hardware/system information (TAU, PERI-DB) • CPU speed, memory in GB, MPI node IDs, … • Application instrumentation (application-specific) • TAU_METADATA() used to insert any name/value pair • Application parameters, input data, domain decomposition • PerfDMF data management tools can incorporate an XML file of additional metadata • Compiler flags, submission scripts, input files, … • Metadata can be imported from / exported to PERI-DB • PERI SciDAC project (UTK, NERSC, UO, PSU, TAMU)
Metadata for Each Experiment Multiple PerfDMF DBs
Performance Data Mining • Conduct parallel performance analysis process • In a systematic, collaborative and reusable manner • Manage performance complexity • Discover performance relationship and properties • Automate process • Multi-experiment performance analysis • Large-scale performance data reduction • Summarize characteristics of large processor runs • Implement extensible analysis framework • Abstraction / automation of data mining operations • Interface to existing analysis and data mining tools
Performance Data Mining (PerfExplorer) • Performance knowledge discovery framework • Data mining analysis applied to parallel performance data • comparative, clustering, correlation, dimension reduction, … • Use the existing TAU infrastructure • TAU performance profiles, PerfDMF • Technology integration • Java API and toolkit for portability • Built on top of PerfDMF • R-project/Omegahat, Octave/Matlab statistical analysis • WEKA data mining package • JFreeChart for visualization, vector output (EPS, SVG)
Performance Data Mining (PerfExplorer v1) K. Huck and A. Malony, “PerfExplorer: A Performance Data Mining Framework For Large-Scale Parallel Computing,” SC 2005.
Relative Comparisons (GTC, XT3, DOE PERI) • Total execution time • Timesteps per second • Relative efficiency • Relative efficiency per event • Relative speedup • Relative speedup per event • Group fraction of total • Runtime breakdown • Correlate events with total runtime • Relative efficiency per phase • Relative speedup per phase • Distribution visualizations Data: GYRO on various architectures
Cluster Analysis count PCA scatterplot min avg max PerfDMF databases topology Data: sPPM on Frost (LLNL), 256 threads
Correlation Analysis Strong negative linear correlation betweenCALC_CUT_BLOCK_CONTRIBUTIONSand MPI_Barrier Data: FLASH on BGL(LLNL), 64 nodes
4-D Visualization 4 “significant” events areselected clusters and correlations are visible Data: FLASH on BG/L (LLNL), 1024 nodes
PerfExplorer v2 – Requirements and Features • Component-based analysis process • Analysis operations implemented as modules • Linked together in analysis process and workflow • Scripting • Provides process/workflow development and automation • Metadata input, management, and access • Inference engine • Reasoning about causes of performance phenomena • Analysis knowledge captured in expert rules • Persistence of intermediate results • Provenance • Provides historical record of analysis results
TAU Integration with IDEs • High performance software development environments • Tools may be complicated to use • Interfaces and mechanisms differ between platforms / OS • Integrated development environments • Consistent development environment • Numerous enhancements to development process • Standard in industrial software development • Integrated performance analysis • Tools limited to single platform or programming language • Rarely compatible with 3rd party analysis tools • Little or no support for parallel projects