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Purpose

Intel Amplifier (aka VTune) supports profiling and evaluation of performance characteristics for single- and multi-threaded programs on all Intel-based hardware platforms. Since 2011, the new name for VTune is Intel Amplifier XE.

Amplifier availability on LRZ's HPC platforms

Amplifier is provided on HPC systems which are based on Intel processors. On non-Intel processors or systems on which no kernel driver is available, only partial functionality may be available. If you encounter any difficulties with the LRZ-specific installations, please contact the LRZ Service Desk for help.

How to use 

You can invoke the tool either via the command line interface (command amplxe-cl) or the GUI (command amplxe-gui). Please type the following command:

module load amplifier_xe  # use 2018 or newer for APS
amplxe-gui

The GUI allows you to build analysis projects, specify an executable as well as various parameters for execution and analysis modes. In particular, profiling of threaded programs (including scalability analysis and identification of parallelization-induced performance problems) is supported.
Please consult the documentation referenced below for a description of the many options this tool offers.

Because the kernel modules for performance-counter based amplifier runs cannot be provided, only a subset of the functionality may be available via the Linux perf infrastructure. 
However, since 2019 this functionality is much more accurate and comprehensive than in the past. See this (off-site) article for further details.

APS

With recent releases, Intel Amplifier XE includes the Application Performance Snapshots (APS),  that provides a quick overview about:

  • MPI parallelism (Linux* only)
  • OpenMP* parallelism
  • Memory access
  • FPU Utilization
  • I/O efficiency

APS can be used without the restrictions of Amplifier, and it is often the first step for code profiling. LRZ users are encouraged to use APS for independent profiling, especially at the beginning of a new project, or after porting to a new machine.
Occasionally, LRZ may ask users to provide APS reports of their production runs.

Running APS

Initialize APS on LRZ machines

module load amplifier_xe  # use 2018 or newer 
source ${AMPLIFIER_XE_BASE}/apsvars.sh 

Run analysis for an application and store results in <dir> (e.g. within a slurm job file):

aps [--result-dir=<dir>] ./myserial.exe
mpiexec <mpiexec_options> aps [--result-dir=<dir>] ./myparallel.exe

Show analysis report based on data from <dir>, output is text and  HTML (e.g. in post-processing):

aps --report=<dir>; firefox <dir>.html
aps-report -a <dir>

For more advanced APS capabilites, please refer to aps and aps-report manual entries, or consult this (off-site) article.

Documentation

  • The documentation for VTune Amplifier is available on the systems via the environment variable $AMPLIFIER_XE_DOC. This includes tutorial material.
  • Manual pages for the commands can be consulted when running with the GUI.
  • Intel VTune Amplifier XE for Linux
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