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Scalasca SCalable performance Analysis of LArge SCale Applications

Scalasca SCalable performance Analysis of LArge SCale Applications

Scalasca

Introduction

Scalasca (SCalable performance Analysis of LArge SCale parallel Applications) is an open-source project developed in the Jülich Supercomputing Centre (JSC) which focuses on analyzing OpenMP, MPI and hybrid OpenMP/MPI parallel applications, yet presenting an advanced and user-friendly graphical interface. Scalasca can be used to help identify bottlenecks and optimization opportunities in application codes by providing a number of important features: profiling and tracing of highly parallel programs; automated trace analysis that localizes and quantifies communication and synchronization inefficiencies; flexibility (to focus only on what really matters), user friendliness; and integration with PAPI hardware counters for performance analysis.

 

Current Version Platforms
1.3.3 SuperMIG, MPP Cluster, ICE Cluster and UV Cluster

Usage

First you need to adjust your environment;

module add scalasca

In order to have all binaries and libraries needed easily accessible. The use of Scalasca consist of 3 phases:

  1. Instrument: (skin)

    Prepare and link the application with the measurement libraries. Normally you modify compile and link commands in a Makefile or by invoking configure. For example, replace

    mpicc -o foo [some options] foo.c
    with 
    scalasca -instrument mpicc -o foo [some options] foo.c

    to produce an instrumented binary that is ready to be executed. Scalasca commands have an alias, such as skin for scalasca -instrument, so you can alternatively use:

    skin mpicc -o foo [some options] foo.c
    If you want to trace OpenMP programs you have to use the corresponding compiler switch: 
    skin mpif90  -openmp [some options] foo.f90
  2. Analyze: (scan)

    Invoke the Scalasca measurement collector and analyzer with

    scalasca -analyze mpiexec [some options] foo.exe [some parameters]
    or 
    scan mpiexec [some options] foo.exe [some parameters]
    which collects measurement data in a new folder, called by default epik_ProgramName_nCPUS_sum. Summarization is performed by default, and tracing is specified via the '-t' flag, e.g., 
    scalasca -analyze -t mpiexec [some options] foo.exe [some parameters]

    Measurements collected by Scalasca are also configured through environment variables or by specifying them in a file called ./EPIK.CONF -- for detailed information refer to the Scalasca Quick Reference.

  3. Examine: (square)

    Start Scalasca's graphical user interface with

    scalasca -examine epik_ProgramName_nCPUS_sum

    or

    square epik_ProgramName_nCPUS_sum
    to explore the analysis report, as in the picture. Scalasca_cube3

  4. Additional Information