Hybrid Programming in HPC – MPI+X

This course will be provided als ONLINE course (using Zoom)

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 NHR@FAU.

Location

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

Start date

Dec 12, 2022
08:45

End date

Dec 14, 2022
16:00

Language

English

Entry level

Advanced

Course subject areas

Parallel Programming

Programming Languages for Scientific Computing

Topics

MPI

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Prerequisites and content levels

Prerequisites:

Basic MPI and OpenMP knowledge as presented in our VSC courses on MPI and OpenMP.
For the hands-on sessions you should know Unix/Linux and either C/C++ or Fortran.
The hands-on labs will be done on the Austrian flagship supercomputers VSC-4 or VSC-5, all participants will get a training user account on VSC-4 or VSC-5 for the duration of the course.

Content levels:

Basic: 0 hours
Intermediate: 1 hour 30 minutes
Advanced: 13 hours 30 minutes

Learn more about course curricula and content levels.

Instructors

Georg Hager (NHR@FAU, Uni. Erlangen), Rolf Rabenseifner (HLRS, Uni. Stuttgart),
Claudia Blaas-Schenner (VSC Research Center, TU Wien)

Agenda

1st day – 12 December 2022

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 – 13 December 2022

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 – 14 December 2022

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)

Handout

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

Registration information

Register via the button at the top of this page.
We encourage you to register to the waiting list if the course is full. Places might become available.

Registration period is from 3 Oct to 30 Nov 2022, and follows the "first come – first served" principle.
Following your successful registration, you will receive further information approx. 1 week before the course.
For the online course we can take a maximum of 40 persons.
Additional registrations will be added to a waiting list.