Registration is now open for CppCon 2021, which starts on October 24 and will be held both in person and online. To whet your appetite for this year’s conference, we’re posting videos of some of the top-rated talks from our most recent in-person conference in 2019 and our online conference in 2020. Here’s another CppCon talk video we hope you will enjoy – and why not register today for CppCon 2021 to attend in person, online, or both!

Practical Memory Pool Based Allocators For Modern C++

by Misha Shalem

Summary of the talk:

Runtime-deterministic memory allocations are a crucial aspect of any safety-critical real-time system. One of the simplest and widely adopted allocation mechanisms used in such systems is a memory pool with fixed block sizes. Unfortunately, the need to know the exact sizes of the memory blocks makes any practical usage of memory pools with standard C++ allocator-based approach rather problematic since users often “hide” real properties of allocations which are made under the hood. For example: STL’s node-based containers like 'std::map' as well as other standard mechanisms like 'std::promise' or 'std::allocate_shared'.

Being a company which focuses on real-time safety-critical applications, we still see a significant value in keeping compatibility with the standard allocator model as well as in following common conventions which are familiar to every C++ developer.

This talk presents an approach which uses a combination of a memory allocator implementation which instruments the code, and an external LLVM-based tool which extracts the instrumentation information and generates static memory pool definitions, allowing the allocator to switch from the heap to a memory pool without any further changes to the code. The presentation will walk through a simplest possible implementation of this approach.