Introduction to Hybrid Programming in HPC @ VSC Vienna

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 all 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 a PRACE training event. It is organized by the VSC Research Center, TU Wien, in cooperation with HLRS and RRZE.

Location

Online course
Organizer: ASC Research Center, TU Wien, Austria

Start date

Jun 15, 2021
20:45

End date

Jun 17, 2021
16:00

Language

English

Entry level

Advanced

Course subject areas

Parallel Programming

Topics

MPI

OpenMP

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Agenda & Content

1st day – 15 June 2021

08:45 Join online
09:00 Welcome
09:05 Motivation
09:15 Introduction
09:30 Programming Models
09:35 - MPI + OpenMP
10:00 Practical (how to compile and start)
10:30 Break
10:45 - continue: MPI + OpenMP
11:30 Break
11:45 - continue: MPI + OpenMP
12:30 Practical (how to do pinning)
13:00 Lunch
14:00 Practical (hybrid through OpenMP parallelization)
15:30 Q & A, Discussion
16:00 End of first day

2nd day – 16 June 2021

08:45 Join online
09:00 - Overlapping Communication and Computation
09:30 Practical (taskloops)
10:30 Break
10:45 - MPI + OpenMP Conclusions
11:00 - MPI + Accelerators
11:30 Tools
11:45 Break
12:00 Programming Models (continued)
12:05 - MPI + MPI-3.0 Shared Memory
13:00 Lunch
14:00 Practical (replicated data)
15:30 Q & A, Discussion
16:00 End of second day

3rd day – 17 June 2021

08:45 Join online
09:00 - MPI Memory Models and Synchronization
09:40 - Pure MPI
10:00 Break
10:15 - Recap - MPI Virtual Topologies
10:45 - Topology Optimization
11:15 Break
11:30 Practical/Demo (application aware Cartesian topology)
12:30 - Topology Optimization (Wrap up)
12:45 Conclusions
13:00 Lunch
14:00 Finish the hands-on labs, Discussion, Q & A, Feedback
16:00 End of third day (course)

Prerequisites and content levels

Prerequisites

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

Content levels

Intermediate: 1 hour 30 minutes
Advanced: 13 hours 30 minutes

Learn more about course curricula and content levels.

Language

English

Course Material

A link to the course material (slides and exercises) will be available at course start.

Teacher

Dr. habil. Georg Hager (RRZE/HPC, Uni. Erlangen), Dr. Rolf Rabenseifner (HLRS, Uni. Stuttgart), Dr. Claudia Blaas-Schenner (VSC Research Center, TU Wien) and David Fischak (tutor; VSC Research Center, TU Wien)

Registration and further information

Registration is closed.

Date, Time, and Location:

15. - 17.06.2021, 09:00 - 16:00, ONLINE COURSE

Registration:

Please register at the PRACE course page: events.prace-ri.eu/event/1173/registrations/850/

Registration period is from 12 April 2021 to 6 June 2021, and follows the "first come – first served" principle.
For the online course we can take a maximum of 40 persons.
Additional registrations will be added to a waiting list.

Fee:

This course is a PRACE Training Center (PTC) event. Therefore, the course is free of charge for all participants from the EU or from PRACE-member countries.