Introduction to Hybrid Programming in HPC and Scaling Workshop

Research & Science
Introduction to Hybrid Programming in HPC and Scaling Workshop


Monday-Tuesday: Introduction to Hybrid Programming in HPC (open to everybody)

Most HPC systems are clusters of shared memory nodes. To use such systems efficiently both memory consumption and communication time has to be optimized. Therefore, hybrid programming may combine the distributed memory parallelization on the node interconnect (e.g., with MPI) with the shared memory parallelization inside of each node (e.g., with OpenMP or MPI-3.0 shared memory). This course analyzes the strengths and weaknesses of several parallel programming models on clusters of SMP nodes. Multi-socket-multi-core systems in highly parallel environments are given special consideration. MPI-3.0 has introduced a new shared memory programming interface, which can be combined with inter-node MPI communication. It can be used for direct neighbor accesses similar to OpenMP or for direct halo copies, and enables new hybrid programming models. These models are compared with various hybrid MPI+OpenMP approaches and pure MPI. Numerous case studies and micro-benchmarks demonstrate the performance-related aspects of hybrid programming.

Hands-on sessions are included on both days. Tools for hybrid programming such as thread/process placement support and performance analysis are presented in a "how-to" section. This course provides scientific training in Computational Science, and in addition, the scientific exchange of the participants among themselves. This course is organized by HLRS, in cooperation with RRZE and VSC (Vienna Scientific Cluster).

Wednesday-Friday: Scaling Workshop (only for customers of HLRS)

In order to increase the efficiency of our users' applications on Hawk, HLRS and HPE offer this workshop to enhance the node-level performance as well as scaling of the codes utilized by participants. By doing so, users can raise the volume as well as quality of their scientific findings while the costs (in terms of core hours) remain constant.

In order to achieve usable efficiency enhancements, it is important to discuss pros and cons of potential solutions. This, however, requires application as well as hardware expertise. Hence, this workshop brings together application and hardware specialists in the shape of users and machine experts.

Target audience: Code owners of applications already running on Hazel Hen or Hawk.

Agenda & Content

Agenda & Content (preliminary)

1st day (Hybrid programming, part 1)

08:45 Registration
09:00   Welcome
09:05   Motivation
09:15   Introduction
09:45   Programming Models
09:45   - Pure MPI
10:05 Coffee Break
10:25   - Topology Optimization
11:05      Practical (application aware Cartesian topology) 
11:45     Topology Optimization (Wrap up)
12:00 Lunch
13:00   - MPI + MPI-3.0 Shared Memory
13:30             Practical (replicated data)
14:00 Coffee break
14:20   - MPI Memory Models and Synchronization
15:00     Practical (substituting pt-to-pt by shared memory) 
15:45 Coffee break
16:00     Practical (substituting barrier synchronization by pt-to-pt)
17:00 End

2nd day (Hybrid programming, part 2)

09:00 Programming Models (continued)
           - MPI + OpenMP
10:30 Coffee Break
10:50     Practical (how to compile and start)
11:30     Practical (hybrid through OpenMP parallelization)
13:00 Lunch
14:00  - Overlapping Communication and Computation
14:20     Practical (taskloops) 
15:00 Coffee Break
15:20  - MPI + OpenMP Conclusions
15:30  - MPI + Accelerators
15:45 Tools
16:00 Conclusions
16:15 Q&A
16:30 End

3rd to 4th day (Scaling Workshop)

9:00 - 17:30 Scaling Workshop

Last day

9:00 - 15:30 Scaling Workshop


Hybrid programming days:
Basic MPI and OpenMP knowledge as presented, e.g., in our Training Courses on MPI and OpenMP.
For the hands-on sessions you should know Unix/Linux and either C/C++ or Fortran in particular.

Scaling workshop:
Your application is running on Hazel Hen and may be already compiled for Hawk.
Further preparation will be communicated by email to all participants.


The course language is English.

Course material
Course material

Hybrid programming days: See (preliminary link, from previous course).


Hybrid programming days: Dr. habil. Georg Hager (RRZE/HPC, Uni. Erlangen), Dr. Rolf Rabenseifner (HLRS, Uni. Stuttgart), Dr. Claudia Blaas-Schenner and Dr. Irene Reichl (VSC Team, TU Wien)

Registration & Further Information

via online registration form. If you want to register only for the Hybrid Programming days, then please register only for days 1+2 in the form.


for registration is Jan. 06, 2020.


Students without Diploma/Master: 25 EUR
Students with Diploma/Master (PhD students) at German universities: 45 EUR
Members of German universities and public research institutes: 45 EUR
Members of universities and public research institutes within EU or PRACE member countries: 90 EUR.
Members of other universities and public research institutes: 180 EUR
Others: 420 EUR

(includes coffee breaks)


Travel Information and Accommodation

see our How to find us page.


HLRS is part of the Gauss Centre for Supercomputing (GCS), which is one of the six PRACE Advanced Training Centres (PATCs) that started in Feb. 2012.
HLRS is also member of the Baden-Württemberg initiative bwHPC-C5.
This course is provided within the framework of the bwHPC-C5 user support. This course is not part of the PATC curriculum and is not sponsored by the PATC program.

Local Organizer

Rolf Rabenseifner phone 0711 685 65530,
Lucienne Dettki phone 0711 685 63894,

Shortcut-URL & Course Number