adventures in mastering the use of performance evaluation tools manuel ríos morales icom 5995...
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Adventures in Mastering the Use of Performance Evaluation Tools
Manuel Ríos MoralesICOM 5995
December 4, 2002
Overview
Project Proposal Original Goals Problems Encountered
Project Changes Revised Goals New Problems
Final Revision
Project Proposal
Original Goals Master a performance evaluation tool and use it to
evaluate the performance of an existing benchmark. Tool selected: AIMS Benchmark: FT kernel of the NPB
Why AIMS? Provides tools for measurement and analysis of
performance of parallel programs. Can be used to highlight problem areas that can be
modified to improve program execution.
Problems Encountered
Installation Quite challenging Required modification of makefiles and debugging of
some modules
Instrumentation Couldn’t be achieved due to bugs in the software.
Problems Encountered (cont.)
Project Changes
Revised Goals Performance evaluation tool changed to Vampir.
New Problems Compilation of the FT benchmark Installation of VampirTrace
Final Revision
Project goals Understanding basic features of Vampir with the use of
an example provided in the Vampir package.
Vampir Analysis Tool
Vampir consists of two packages: Vampir: Tracefile visualization program with a
graphical user interface for XWindows desktops.
VampirTrace: Instrumented MPI library to link with the user code for automatic tracefile generation on a parallel platform.
VampirTrace
Tool for MPI applications that produces tracefiles that can be analyzed with Vampir.
Records all calls to the MPI library and all transmitted messages.
Allows defining and recording arbitrary user defined events.
Using it requires relinking the application with the VampirTrace profiling library.
VampirTrace (cont.)
mpicc -o test test.c -L/$HOME/VampirTrace/lib/libVT.a –lVT
patch_mpicc Modifies mpicc command to include the –vt option
Mpicc –vt –o test test.c
Vampir
Tool for visualization and analysis of MPI programs
Understand the application behavior Analyze the performance of subroutines or code
blocks Learn about communication patterns, parameters
and performance Identify communication hotspots
Vampir (cont.)
Basics Loading Tracefiles Displays
Global Timeline Display
Global Timeline Display (cont.)
It will automatically open when paused or finished loading a tracefile.
Shows all analyzed state changes for each process over the complete period of time in one display.
Zoom ability allows getting detailed information of the runtime behavior of the traced program.
Activity Chart Display
Shows a statistic about the time spent in each activity individually for each process defined in the tracefile.
Summary Chart Display
Displays the sum of the time consumed by all instrumented activities over all selected processes.
Final Thoughts
Tools that facilitate the instrumentation and visualization of parallel program execution are invaluable.
Programmers can benefit from using these tools since the help highlight any problem areas that can be modified to improve program execution.
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