Jun 14 – 18, 2021
Online event
Europe/Zurich timezone

Academic programme

The school will focus on the theme of Scientific Software for Heterogeneous Architectures. The complete programme will offer 24 hours of lectures, hands-on exercises and group assignment work, as well as an additional student presentations session, and a special evening lecture.

  • Introduction lecture

    Preparing for the HL-LHC computational challenge
    by Danilo Piparo (CERN)

    • HEP data processing and analysis workflows
    • Upgrades of the LHC accelerator and experiments
    • Evolution of hardware and computing infrastructure
    • Impact on HEP data processing software
  • Track 1: Technologies and Platforms

    4 hours of lectures and 2 hours of group assignment
    by Andrzej Nowak

    Introduction to efficient computing

    • The evolution of computing hardware and what it means in practice
    • The seven dimensions of performance
    • Controlling and benchmarking your computer and software
    • Software that scales with the hardware
    • Advanced performance tuning in hardware

    Data-oriented design

    • Hardware vectorization in detail – theory vs. practice
    • Software design for vectorization and smooth data flow
    • How can compilers and other tools help?

    Hardware evolution and heterogeneity

    • Accelerators, co-processors, heterogeneity
    • Memory architectures, hardware caching and NUMA
    • Compute devices: CPU, GPU, FPGA, ASIC etc.
    • The role of compilers

    Summary and future technologies overview

    • Teaching program summary and wrap-up
    • Next-generation memory technologies and interconnect
    • Future computing evolution
  • Track 2: Parallel and Optimised Scientific Software

    4 hours of lectures, 1.5 hours of group assignment, and 4 hours of hands-on exercises
    by Sebastien Ponce (CERN)
    and Danilo Piparo (CERN)
    exercises assisted by Arthur Hennequin (CNRS)

    Writing parallel software (D.Piparo)

    • Amdahl's and Gustafson's laws
    • Asynchronous execution
    • Finding concurrency, task vs. data parallelism
    • Using threading in C++ and Python, comparison with multi-process
    • Resource protection and thread safety
    • Locks, thread local storage, atomic operations

    Modern programming languages for HEP (S.Ponce)

    • Why Python and C++ ?
    • Recent evolutions: C++ 11/14/17
    • Modern features of C++ related to performance
    • Templating versus inheritance, pros and cons of virtual inheritance
    • Python 3, and switching from Python 2

    Optimizing existing large codebase (S.Ponce)

    • Measuring performance, tools and key indicators
    • Improving memory handling
    • The nightmare of thread safety
    • Code modernization and low level optimizations
    • Data structures for efficient computation in modern C++

    Practical vectorization (S.Ponce)

    • Measuring vectorization level
    • What to expect from vectorization
    • Preparing code for vectorization
    • Vectorizing techniques in C++: intrinsics, libraries, autovectorization
  • Track 3: Programming for Heterogeneous Architectures

    4 hours of lectures, 1.5 hours of group assignment, and 4 hours of hands-on exercises
    by Dorothea vom Bruch (CPPM/CNRS)
    and Daniel Campora (University of Maastricht)

    Scientific computing on heterogeneous architectures (D.vom Bruch)

    • Introduction to heterogeneous architectures and the performance challenge
    • From general to specialized: Hardware accelerators and applications
    • Type of workloads ideal for different accelerators
    • Trade-offs between multi-core and many-core architectures
    • Implications of heterogeneous hardware on the design and architecture of scientific software
    • Embarrassingly parallel scientific applications in HPC and CERN

    Programming for GPUs (D.vom Bruch)

    • From SIMD to SPMD, a programming model transition
    • Thread and memory organization
    • Basic building blocks of a GPU program
    • Control flow, synchronization, atomics

    Performant programming for GPUs (D.Campora)

    • Data locality, coalesced memory accesses, tiled data processing
    • GPU streams, pipelined memory transfers
    • Under the hood: branchless, warps, masked execution
    • Debugging and profiling a GPU application

    Design patterns and best practices (D.Campora)

    • Good practices: single precision, floating point rounding, avoid register spilling, prefer single source
    • Other standards: SYCL, HIP, OpenCL
    • Middleware libraries and cross-architecture compatibility
    • Reusable parallel design patterns with real-life applications
  • Additional lectures

    Student lightning talks session

    Special evening lecture
    Future of the Universe and of Humanity
    by Ivica Puljak (University of Split)