from 30 November 2017 to 1 December 2017
LRZ
CET timezone

This course teaches performance engineering approaches on the compute node level. "Performance engineering" as we define it is more than employing tools to identify hotspots and bottlenecks. It is about developing a thorough understanding of the interactions between software and hardware. This process must start at the core, socket, and node level, where the code gets executed that does the actual computational work. Once the architectural requirements of a code are understood and correlated with performance measurements, the potential benefit of optimizations can often be predicted. We introduce a "holistic" node-level performance engineering strategy, apply it to different algorithms from computational science, and also show how an awareness of the performance features of an application may lead to notable reductions in power consumption.

The course is a PRACE Advanced Training Center event.

  • Introduction
    • Our approach to performance engineering
    • Basic architecture of multicore systems: threads, cores, caches, sockets, memory
    • The important role of system topology
  • Tools: topology & affinity in multicore environments
    • Overview
    • likwid-topology and likwid-pin
  • Microbenchmarking for architectural exploration
    • Properties of data paths in the memory hierarchy
    • Bottlenecks
    • OpenMP barrier overhead
  • Roofline model: basics
    • Model assumptions and construction
    • Simple examples
    • Limitations of the Roofline model
  • Pattern-based performance engineering
  • Optimal use of parallel resources
    • Single Instruction Multiple Data (SIMD)
    • Cache-coherent Non-Uniform Memory Architecture (ccNUMA)
    • Simultaneous Multi-Threading (SMT)
  • Tools: hardware performance counters
    • Why hardware performance counters?
    • likwid-perfctr
    • Validating performance models
  • Roofline case studies
    • Dense matrix-vector multiplication
    • Sparse matrix-vector multiplication
    • Jacobi (stencil) smoother
  • Optional: The ECM performance model
Starts 30 Nov 2017 09:00
Ends 1 Dec 2017 17:00
CET
LRZ
Hörsaal H.E.009 (Lecture hall)
Boltzmannstr. 1 85748 Garching b. München Germany

Prerequisites:

Participants must have basic knowledge in programming with Fortran or C.
Language: English
Further information: Travel info, hotel info, course page at LRZ
Registration: Via https://events.prace-ri.eu/event/632/registration/register

Teachers:

Dr. Georg Hager/RRZE