Höchstleistungsrechenzentrum Stuttgart

Hackathon: Porting and Optimization for Hunter

Participation in English or German is possible.
Learn how to optimize your program for HLRS's system Hunter.

The Hackathon consists of two parts

  • a preparation phase with a discussion of your project and goals for the hackathon, taking place March 23 (online),

  • the actual coding phase, where you will work towards the defined goal, see below, and port your code to Hunter, taking place April 13-17 (hybrid).

HLRS's current APU based supercomputer system called “Hunter” is since 2025. As for every new system, users have to spend some effort into porting their code and workflow to the new environment. Furthermore, the vast majority of Hunter’s compute power will be delivered by the GPU part of the APU, which requires users to adapt their hot loops in order to offload them to the GPUs. In this hackathon we will hence support our users in doing both. This hackathon focuses on traditional scientific codes but also dedicates time to users running part or all of their workflows with AI.

In order to offload to GPUs, multiple programming models (HIP, OpenMP device offloading, PSTL/do concurrent) are available depending on the programming language used. If you are unfamiliar with them, please have a look at the recordings in the self-study corner. In the preparation phase, pros and cons of those models based on your situation could be discussed if you are just starting porting, and you and the support staff will decide together which are suitable goals for the coding phase and how to proceed.

In the coding phase, you will work towards your defined goals supported by HLRS user support staff, HPE and AMD specialists. So, most probably you will be porting and optimizing your code for the new system, i.e. building with suitable compilers, using CPE's performance analysis tools to identify 'hot loops' and offloading them to the GPU will be the main tasks.

Due to the large number of groups using HLRS’ systems but limited support staff, the number of participants needs unfortunately to be limited. In order to use the system as efficiently as possible, we have to focus on groups holding medium and large compute time budgets. We hence reserve the right to select attendees!

To allow for easy attendance, we decided to provide this workshop in a hybrid fashion. Besides meeting in person at HLRS, we will also setup breakout rooms in a Zoom session, which enable remote participants to communicate as well as share screens and remote control applications with support staff, hence providing the same options of interaction as meeting in person.

Target audience: Groups holding a compute time budget to be used on Hunter.

Veranstaltungsort

This hybrid event will take place online and at
HLRS, University of Stuttgart
Nobelstraße 19
70569 Stuttgart, Germany
Location and nearby accommodations

Veranstaltungsbeginn

23. März 2026
09:00

Verstaltungsende

17. Apr. 2026
13:00

Sprache

Englisch

Einstiegslevel

Fortgeschritten

Themenbereiche

Bootcamp/Hackathon

Hardware-Beschleuniger

Performance-Optimierung & Debugging

Themen

Künstliche Intelligenz

Big Data

Code-Optimierung

Deep Learning

GPU-Programmierung

MPI

MPI+OpenMP

OpenMP

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Prerequisites and content levels

Prerequisites

To participate in the Hackathon, you should already have an account on Hunter and make sure to be able to access Hunter from the place you plan to work, e.g. via VPN. Please check with your PI if you are unsure if VPN access is enabled for your account. See https://kb.hlrs.de/platforms/index.php/VPN for how to set up VPN.

  • Furthermore, kindly provide the following details by submitting an email to training(at)hlrs.de and CC to Björn Dick: dick(at)hlrs.de by the workshop registration deadline.
    • Scientific domain you are working in,
    • name of your code including URL (if available),
    • Numerical approaches (should not be the majority of the provided details),
    • name of the compute time budget used,
    • programming language,
    • programming models used (MPI, OpenMP, etc.),
    • list of dependencies/libraries,
    • known issues with specific compilers
    • information on porting efforts done so far
    • IO requirements (what is written to disk? with which frequency? number of files generated per each of those I/O events? volume of those files?)
    • Size of your test case in terms of number of Hunter nodes used as well as expected runtime.
  • Running AI codes also necessitates information about:
    • The user's AI software stack.
    • IO requirements (e.g., dataset size, number of files, model size, number of checkpoints)
    • The workflow along with computational requirements (e.g., number of GPUs needed for model training/fine-tuning and hyperparameter tuning).
  • Additionally, we require that you bring your own code including a test case which is set up according to the following rules:
  • use case selection:
    • When processing the test case, your code should have a behavior and profile which is as close as possible to that of current and future production runs.
    • If possible, the test case should be representative for those production runs of your group which consume the largest part of your compute time budget.
  • number of GPUs:
    • In order to be representative, the test case should be in size comparable to the respective current and future production runs.
    • In order to save valuable resources and to allow for a productive workflow, it should, however, be as small as possible.
    • So, please, be prepared to reduce the size of your test case during the workshop! This can often be achieved while staying representative by reducing the simulated domain or resolution and keep the computational load per GPU constant ("weak down scaling").
  • wall time:
    • In order to allow for a productive workflow, the wall time should be a few minutes only.
    • At the same time, it should cover all important parts of the code, i.e. computation, communication and I/O.
    • So take into account to reduce the number of simulated time steps and be prepared to increase I/O frequency to render investigation of I/O possible within such a low number of timesteps.

Please have in mind that it's possible to bring multiple test cases with you. This allows to cover different use cases and figure out hotspots with a production-alike sized case while doing the porting on a smaller case which allows for a simplified workflow.


If you are unsure about how to set up your test case, please contact Björn Dick (see contact data below).

In general the language of instruction is German, but can be changed to English if required.

Instructors

HLRS, HPE and AMD user support staff

Learning outcomes

  • Knowledge about and practical experience with deploying your code in CPE.
  • Overview of available programming models for AMD APUs/GPUs and how to use them.
  • Important knowledge about how to optimize your code for the APU/GPU and which performance metrics are important.

Handout

If handouts will be available, participants will get them as PDFs.

Dates

The Hackathon consists of two parts

  • a preparation phase with a discussion of your project and goals for the hackathon, taking place March 23,

  • the actual coding phase, where you will work towards your goal and optimize your code for Hunter, taking place April 13-17.

The first phase will be a virtual event. The second phase will be offered as a hybrid event. Please select for the hybrid event on which days you plan to be on-site at HLRS.

We expect you to participate in both phases, in the first at least to discuss your project and goals.

If you need a recap on APUs, OpenMP target offload, or AMD tools and are a subscriber of the HLRS training news, self-study materials are available.

 

Agenda

- preliminary -

Local times: Central European Time Zone (Berlin).
Communication format: Face-to-face, via Slack, Zoom, and email.

Preparation Phase

March 23, 9-17 h
  • Tutor assignment
  • Development of agenda for your code
  • Develop to-dos (Compile & Profile)
  • Set up of test case together with tutors
  • Agree on checkpoints with tutors until the hackathon starts

Coding Phase

April 13-17, 8:45-9:00 (Monday opening at 12:45 to facilitate travelling to Stuttgart)Local registration/drop in to Zoom
April 13-17, 9:00-17:30 (Monday opening at 13:00 and Friday closing at 13:00 to facilitate travelling to/from Stuttgart)Working on your code and workflow together with HLRS/HPE/AMD support staff

Hybrid course

This course will be hybrid, i.e. it will take place at HLRS on-site, but it will also be possible to attend remotely. Participants, remote as well as on-site, have to be aware and agree that they might appear in the live video stream taken by a camera in the back of the lecture room or by a webcam on laptops. The live stream will not be saved. We strongly recommend to attend this course on-site since on-site attendance is much more effective and efficient in our experience. Therefore we might give priority to on-site over remote participants during registration.

Registration information

Apply for this course via the button at the top of this page (will be available soon).

Please submit information about your code, see section Prerequisites and content levels, as soon as you applied for the workshop via email to training@hlrs.de. You can book individual days according to your and your project's needs, attending a full workshop in this case is not necessary.

Please be aware that the talks might be recorded. You declare that you are aware of and consent to the recording by applying.

Please apply before March 22, 2026.

Fees

  • Students without master’s degree or equivalent at a German university: 0 Euro
  • PhD students or employees at a German university or public research institute: 0 Euro

Further fee categories can be found in the registration page.

Our course fees include coffee breaks (in classroom courses only).

Contact

Björn Dick phone 0711 - 685 87189, bjoern.dick(at)hlrs.de
Tobias Haas phone 0711 685 87223, training(at)hlrs.de

HLRS Training Collaborations in HPC and AI

HLRS is part of the Gauss Centre for Supercomputing (GCS), together with JSC in Jülich and LRZ in Garching near Munich. SIDE is the German National Competence Centre (NCC) for High-Performance Computing. HLRS is also a member of the Baden-Württemberg initiative bwHPC. 
Since 2025, HLRS has been coordinating one of the AI Factories of the EuroHPC JU: HammerHAI. 

Further courses

See the training overview and the Supercomputing Academy pages.

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Kontakt & Standort

+49 711 685-87269 info(at)hlrs.de

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