C++ for High Performance Computing

There was no defined memory model for concurrency in C or C++ prior to the ISO 2011 C and C++ standards. This means that any code exploiting concurrency relies on implementation and undefined behaviour for the specific compiler and hardware used. This makes it extremely difficult to determine if a program is correct and renders code non-portable. Having a memory model enables one to determine whether or not a program is correct and makes it easier to write portable code.

The 2011 C++ standard introduced into C++ support for concurrency, e.g., support for memory models, threads, mutexes, locks, condition variables, and atomics. The C++ memory model is concerned with how structures are laid out in memory, and, how memory locations can be used concurrently to produce well-defined computational results, e.g., by avoiding data races. The latter is supported, at the lowest level, by atomic stores, loads, and read-modify-write operations; and understanding the synchronizes-with and happens-before relationships.

This class will focus on:

  1. understanding move semantics, how moving is implemented, and when to use std::move and std::forward,
  2. understanding some of the important lower-level aspects (e.g., atomics, synchronizes-with, happens-before), and,
  3. how to make use of higher-level C++ constructs such as promises, futures, threads, locks, and condition variables.

Instructor: Paul Preney, SHARCNET, University of Windsor.

Prerequisites: The attendee is expected to know how to write procedural and object-oriented C++ code (C++98 or newer). If familiarity with C++ is weak, the attendee is expected to have intermediate to advanced experience writing (i) object-oriented code, (ii) concurrent code that exploits multithreading (e.g., Java, C/C++ with Pthreads, and/or OpenMP), and, before the class, (iii) review std::vector, std::array, as well as learn how to write and use a C++ class including at least the default and copy constructors; destructor; and copy assignment operator.

NOTE: The aforementioned links are for reference only and are not tutorials.