Difference between revisions of "Intel VTune"

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The Intel VTune™ Amplifier can be used to identify and analyse various aspects in both serial and parallel programs.
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The Intel VTune™ Amplifier can be used to identify and analyse various aspects in both serial and parallel programs and can be used for both [[OpenMP]] and [[MPI]] applications.  
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__TOC__
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== Usage ==
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The following general profiling options are available:
  
 
* Hotspot Analysis
 
* Hotspot Analysis
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* False Sharing
 
* False Sharing
  
One usually starts off with the hotspot analysis. It identifies compute-intensive parts in the code and also evaluates the utilization of the available hardware. It is important not to neglect the serial part, as it can seriously weigh down the performance of the application no matter how efficiently parallelised the rest may be. Overhead and waiting time are collected for OpenMP applications. Other types of analysis as well as the option of a custom one are available for a finer tuning.
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=== Hotspot Analysis ===
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== Intel VTune on the RWTH Cluster ==
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[[File:Intel-VTune-Hotspot.png|500px]]
  
Execute this command to print all available versions of the Intel VTune module (among other Intel modules):
 
  
module apropos intel
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The hotspot analysis is typically the first analysis done in the progress of optimization. It identifies compute-intensive parts in the code and also evaluates the utilization of the available hardware. The summary window should open automatically by default. There, when using multiple [[OpenMP]] Threads, both the measured serial and parallel times are shown as well as an estimated ideal parallel time to give you an idea of how much improvement may be possible. Next, there should be a section listing the different [[OpenMP]] regions in your code and ranking them by improvement potential. The bottom-up window shows the most time-consuming functions, i.e. the hotspots of the code. Issues can be resolved by viewing and editing the actual code lines with the source editor.
  
DO NOT use the versions intelvtune/XE2018-u03 and intelvtune/XE2019-u01 as they influence the performance of the nodes negatively and might produce unreadable results!
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It is important not to neglect the serial parts of a code, as these can seriously weigh down the performance of the application no matter how efficiently parallelised the rest may be.  
It is recommended to load the latest update.
 
To load the GUI and run analyses from there, execute this command:
 
  
amplxe-gui
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== Concurrency Analysis ==
  
  

Revision as of 10:59, 16 April 2019

The Intel VTune™ Amplifier can be used to identify and analyse various aspects in both serial and parallel programs and can be used for both OpenMP and MPI applications.

Usage

The following general profiling options are available:

  • Hotspot Analysis
  • Concurrency Analysis
  • Hardware Performance Counter Support
  • IO waits
  • False Sharing

Hotspot Analysis

Intel-VTune-Hotspot.png


The hotspot analysis is typically the first analysis done in the progress of optimization. It identifies compute-intensive parts in the code and also evaluates the utilization of the available hardware. The summary window should open automatically by default. There, when using multiple OpenMP Threads, both the measured serial and parallel times are shown as well as an estimated ideal parallel time to give you an idea of how much improvement may be possible. Next, there should be a section listing the different OpenMP regions in your code and ranking them by improvement potential. The bottom-up window shows the most time-consuming functions, i.e. the hotspots of the code. Issues can be resolved by viewing and editing the actual code lines with the source editor.

It is important not to neglect the serial parts of a code, as these can seriously weigh down the performance of the application no matter how efficiently parallelised the rest may be.

Concurrency Analysis

References

Tutorials by Intel [1]

Intel VTune™ Amplifier Performance Analysis Cookbook [2]