GPU expert (EP-AIP-2021-79-LD)

  • CERN
  • Geneva, Geneve, Switzerland
  • 07/07/2021
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Job Description

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. Using the world's largest and most complex scientific instruments, they study the basic constituents of matter - fundamental particles that are made to collide together at close to the speed of light. The process gives physicists clues about how particles interact, and provides insights into the fundamental laws of nature. Find out more on

Job Description


Would you like to coordinate the operation of a heterogeneous computing farm (CPU+GPU) designed to reconstruct collision events at the Large Hadron Collider synchronous with data taking? Are you an expert in GPU architectures and parallel programming who enjoys supporting developers in their programming and optimisation tasks? Then join the ALICE Experiment and contribute to the success of data taking with the experiments new common online/offline system called O2.

ALICE (A Large Ion Collider Experiment, is a dedicated heavy ion experiment at the Large Hadron Collider (LHC). The ALICE Collaboration is studying the physics of strongly interacting matter at extreme energy densities and temperatures. In Run 3+4 (2022-2029) ALICE will operate at a peak Pb-Pb collision rate of 50 kHz. All events will be read out, reconstructed synchronously with data-taking with the essential support from GPUs, compressed and written to permanent storage without any selective trigger. This will allow ALICE to assess rare probes with large backgrounds, for which data reduction with online triggers is not possible.


Within the ALICE Physics and Computing group (EP-AIP), you will play a leading role in the operation of the ALICE O2 Event Processing Nodes (EPNs) and support activities associated with the development of efficient code for hardware accelerated platforms. Your functions will include:

  • Detailed organisation of the real-time operation of the EPN including the training and organisation of the shift crew.
  • Act as an interface between the EPN project and ALICE Run Coordination.
  • Provide support for the offline operation of the EPN and act as an interface between the EPN project and Grid Coordination.
  • Provide high-level consultancy and expert help to the software developers working on the performance optimisation of the algorithms, and developing code for GPUs.
  • Provide expert support on GPU specific performance evaluation, optimisation and debugging tools.
  • Organise and participate in software testing, validation and continuous integration including follow up of issues with vendors and external developers.


Master's degree or PhD or equivalent relevant experience in the field of computing or physics or a related field.


  • Extensive experience with coordination, documenting and presenting technical status to collaborators and executives.
  • Experience with leadership of teams.
  • Experience with parallel programming.
  • Extensive experience with supporting developers in code optimisation on GPUs.
  • Experience with software integration and validation.

Technical competencies:

  • Knowledge of programming techniques and languages: modern C++ (C++11, 14, 17), HIP, OpenCL.
  • Knowledge and application of software life-cycle tools and procedures: git, JIRA.
  • Extensive technical knowledge of GPU and CPU architectures.

Behavioural competencies:

  • Setting direction: setting clear, challenging and attainable objectives; defining and communicating performance indicators; ensuring that individual staff members fully understand their tasks, roles and responsibilities.
  • Solving problems: identifying, defining and assessing problems, taking action to address them; anticipating obstacles; assessing alternative solutions in order to have a fall-back plan.
  • Communicating effectively: expressing opinions, ideas and suggestions with conviction and in a logical/structured manner; keeping to the point.
  • Achieving results: having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind; defining clear objectives, milestones and deliverables before initiating work/ project.
  • Learning and sharing knowledge: sharing knowledge and expertise freely and willingly with others; coaching others to ensure knowledge transfer.

Language skills:

Spoken and written English or French: ability to understand and speak the other language in professional contexts. Ability to draw-up technical specifications and/or scientific reports and to make oral presentations in at least one of the two languages.

Additional Information

Eligibility and closing date:

Diversity has been an integral part of CERN's mission since its foundation and is an established value of the Organization. Employing a diverse workforce is central to our success. We welcome applications from all Member States and Associate Member States.

This vacancy will be filled as soon as possible, and applications should normally reach us no later than 30.07.2021 at 12:00pm (noon Geneva time).

Employment Conditions

Contract type: Limited duration contract (5 years). Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

These functions require:

  • Participation in a regular stand-by duty, including nights, Sundays and official holidays.
  • Work during nights, Sundays and official holidays.

Job grade: 6-7

Job reference: EP-AIP-2021-79-LD

Benchmark Job Title: Computing Engineer