Tutorial

Analyze MPI Applications with Intel® Trace Analyzer and Collector and Intel® VTune™ Profiler

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ID 773180
Date 3/31/2023
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Document Table of Contents
Document Table of Contents x
Analyze MPI Applications with Intel® Trace Analyzer and Collector and Intel® VTune™ Profiler
Analyze MPI Applications with Intel® Trace Analyzer and Collector and Intel® VTune™ Profiler x
Prerequisites Starting Intel® Trace Analyzer Starting Intel® VTune™ Profiler Analyzing an MPI Application Summary Notices and Disclaimers
Analyzing an MPI Application x
Optimizing MPI Communications Improving Intra-process Performance
Optimizing MPI Communications x
Prepare for Analysis Ungroup MPI Functions Detect Serialization in Function Profile and Message Profile Compare Original Trace File With Idealized Trace File Remove Serialization Compare Two Trace Files Analyze Optimized Communications
Improving Intra-process Performance x
Run Basic Hotspots Analysis Interpret Results
Analyze MPI Applications with Intel® Trace Analyzer and Collector and Intel® VTune™ Profiler

Compare Original Trace File With Idealized Trace File

See your application under the ideal circumstances and compare the original trace file with the idealized one to isolate problematic interactions.

Create the idealized trace:

  1. In the poisson_sendrecv.single.stf view, select Advanced > Idealization, or use the toolbar button.

  2. In the Idealization dialog box, check the idealization parameters. By default, Intel Trace Analyzer stores the idealized trace in the local folder where the original trace file was opened. The default name of the new ideal trace file is the input trace file name with the suffix ideal added before the .stf extension.

  3. Click Start to idealize the trace poisson_sendrecv.single.stf.



To get more information on idealization, refer to the Idealization Dialog Box section of the Intel® Trace Analyzer User and Reference Guide.

Compare the original trace file with the idealized trace:

  1. In the poisson_sendrecv.single.stf view, select Advanced > Imbalance Diagram or press the toolbar button.

  2. In the Imbalance Diagram dialog box, press the Open Another File button, navigate to the idealized trace poisson_sendrecv.ideal.stf and select it.



  3. Click OK.

  4. In the Imbalance Diagram window, click the Total Mode button and select Breakdown Mode.



This chart shows you a breakdown of the interconnect vs. imbalance overhead in your application, as well as which MPI routines are at fault. You can see that MPI_Sendrecv is the most time-consuming function. The imbalance weight is displayed in the light purple color and comprises about 10% for the MPI_Sendrecv function. This is the time the processes spend waiting for each other.

Parent topic: Optimizing MPI Communications
Level Two Title