Intel Trace Analyzer & Collector#

Purpose#

Debugging MPI applications is notoriously hard. The Intel Trace Analyzer & Collector (ITAC) can be used to generate a trace while running an application, and visualizing it later for analysis.

Prerequisities#

You will need an MPI program (C/C++ or Fortran) to instrument and run.

Step by step#

The following steps are the easiest way to use the Intel Trace Analyzer, however, more sophisticated options are available.

Load the relevant modules. The exact modules may differ from system to system, but will typically include the itac module and a compatible Intel toolchain, e.g.,
```
$ module load intel/2019a
$ module load itac/2019.2.026
```

Note

Users of the UAntwerpen clusters should load the inteldevtools module instead, which makes also available Intel’s debugger, VTune, Advisor and Inspector development tools.

Compile your application so that it can generate a trace:
```
$ mpiicc -trace myapp.c -o myapp
```
where myapp.c is your C/C++ source code. For a Fortran program, this would be:
```
$ mpiifort -trace myapp.f -o myapp
```

Run your application using a PBS script such as this one:

#!/bin/bash -l
#PBS -N myapp-job
#PBS -l walltime=00:05:00
#PBS -l nodes=4

module load intel/2019a
module load itac/2019.2.026
# Set environment variables for ITAC.
# Unfortunately, the name of the script differs between versions of ITAC
source $EBROOTITAC/bin/itacvars.sh

cd $PBS_O_WORKDIR

mpirun -trace ./myapp

When the job is finished, check whether files with names myapp.stf.* have been generated, if so, start the visual analyzer using:
```
$ traceanalyzer myapp.stf
```

Further information#

Intel’s ITAC documentation