Virtual Institute — High Productivity Supercomputing

41st VI-HPS Tuning Workshop (JSC/RWTH Aachen, Germany) - ONLINE


Monday 07th - Friday 11th February 2022


The workshop will be held online, using the Zoom videoconference platform.

Organising Institutions



This workshop organised by VI-HPS, Jülich Supercomputing Centre & RWTH Aachen ITC will:

  • give an overview of the VI-HPS programming tools suite
  • explain the functionality of individual tools, and how to use them effectively
  • offer hands-on experience and expert coaching assistance using the tools
    with your own application running on multi-GPU compute nodes

On completion participants should be familiar with common performance analysis and diagnosis techniques and how they can be employed in practice (on a range of HPC systems). Those who prepared their own application test cases will have been coached in the tuning of their measurement and analysis, and provided optimization suggestions.

Programme Overview

Presentations and hands-on sessions are planned on the following topics:

  • Setting up, welcome and introduction
  • APR performance reports
  • MUST runtime error detection for MPI
  • Caliper event annotation, logging & profiling
  • Nsight system-wide and CUDA kernel profiling
  • PAPI hardware performance counters
  • Score-P instrumentation and measurement
  • CUBE profile processing and exploration
  • TAU performance system
  • Scalasca automated trace analysis
  • Vampir interactive trace analysis
  • Paraver/Extrae/Dimemas trace analysis and performance prediction
  • ... and potentially others to be added

A brief overview of the capabilities of these and associated tools is provided in the VI-HPS Tools Guide.

The workshop will be held in English and run from 09:00 to not later than 18:00 CET each day, with breaks.

Class capacity is limited to support close interaction between instructors/assistants and participants, therefore priority will be given to applicants with parallel codes already running on the workshop computer system (JUWELS), and those bringing codes from similar GPU-accelerated Linux cluster systems to work on. Participants are encouraged to prepare their own GPU-accelerated MPI, OpenMP and hybrid MPI+OpenMP heterogeneous parallel application codes for analysis. Codes using multiple GPUs via OpenACC, OpenCL or CUDA will be given priority.

Programme in Detail (provisional) - all times given as CET (UTC+1)

Day 1: Monday 07 February
09:00 Welcome [Brian Wylie, JSC & Christian Terboven, RWTH] Introduction to Zoom [Cédric Valensi, UVSQ] Building and running TeaLeaf_CUDA on JUWELS Booster [Marc Schlütter, JSC]
  • ARM Performance Reports [JSC/ARM]
10:30 (break)
11:00 MUST runtime error detection for MPI [Joachim Protze, RWTH]
  • MUST hands-on exercises
12:30 (lunch)
14:00 Hands-on coaching to apply APR & MUST to analyze participants' own code(s).
15:30 (break)
16:00 Caliper annotation, logging & profiling [David Böhme, LLNL]
  • Caliper hands-on exercises
17:30 Schedule for remainder of workshop
18:00 (adjourn)
Day 2: Tuesday 08 February
09:00 Jupyter-JSC webservice
10:30 (break)
11:00 Nsight Compute CUDA kernel profiler [Felix Schmitt, Nvidia]
  • Nsight Compute hands-on exercises
12:30 (lunch)
14:00 Hands-on coaching to apply Nsight tools to analyze participants' own code(s).
15:30 (break)
16:00 PAPI for CUDA & NVML [Guiseppe Congiu, UTK-ICL]
  • PAPI hands-on exercises
17:30 Schedule for remainder of workshop
18:00 (adjourn)
Day 3: Wednesday 09 February
09:00 Score-P instrumentation & measurement toolset [Marc Schlütter, JSC]
10:30 (break)
11:00 Hands-on coaching to apply Score-P/CUBE to analyze participants' own code(s).
12:30 (lunch)
14:00 Hands-on coaching to apply Score-P/CUBE to analyze participants' own code(s).
15:30 (break)
16:00 TAU performance system [Sameer Shende, UOregon]
17:30 Review of day and schedule for remainder of workshop
18:00 (adjourn)
Day 4: Thursday 10 February
09:00 Scalasca automated trace analysis [Markus Geimer, JSC]
  • Scalasca hands-on exercises
Vampir interactive trace analysis [Bert Wesarg, TUDresden]
  • Vampir hands-on exercises
10:30 (break)
11:00 Paraver tracing tools suite [Judit Giménez, German Llort & Lau Mercadal, BSC]
12:30 (lunch)
14:00 Review
Hands-on coaching to apply Scalasca/Vampir & Paraver to analyze participants' own code(s).
15:30 (break)
16:00 Hands-on coaching to apply tools to analyze participants' own code(s).
17:30 Review of workshop
18:00 (adjourn)

Hardware and Software Platforms

JUWELS Booster Module: 936 BullSequana XH2000 compute nodes with two 24-core AMD EPYC Rome 7402 CPUs (each with 512GB DDR memory) and four NVIDIA Ampere A100 GPUs (each with 40GB HBM2e), with 200 Gb/s HDR InfiniBand interconnect.

The GPU-accelerated JUWELS Booster Module of the local heterogeneous HPC system is the primary platform for the workshop and will be used for the hands-on exercises. Course accounts will be provided during the workshop to participants without existing accounts. Other systems where up-to-date versions of the tools are installed can also be used when preferred, though support may be limited and participants are expected to already possess user accounts on non-local systems. Regardless of whichever external systems they intend to use, participants should be familiar with the relevant procedures for compiling and running their parallel applications (via batch queues where appropriate).


Registration form: the number of participants is limited and early registration is recommended. Selection will be made based on the information provided when registering.

NB: A separate JUWELS Booster Tuning & Scaling Workshop 7-11 March 2022 is organised for code-teams who have GPU-enabled codes already running on multiple nodes of JUWELS Booster looking to optimize performance and scale effectively to many more nodes. This VI-HPS workshop familiarising with basic use of available tools to understand multi-node/multi-GPU execution performance will be a good foundation for preparing potential participants and their applications for the follow-on workshop.


Tuning Workshop Series

Cédric Valensi
Université de Versailles Saint-Quentin-en-Yvelines
Phone: +33 1 77 57 59 36 / +33 1 39 25 52 26
Email: cedric.valensi[at]

Local Arrangements

Brian Wylie
Jülich Supercomputing Centre
Phone: +49 (0)2461 61-6589
Email: b.wylie[at]