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.