what is memory footprint?

The memory footprint of an application refers to the amount of memory that the application uses. It includes various types of memory allocations, such as heap memory, which is often responsible for the majority of an application's memory footprint. Heap memory is dynamically allocated memory that is used for long-lived data structures and objects in an application. It is created using functions like malloc, calloc, or realloc, and it remains allocated until explicitly freed.

In the context of the WWDC session "Analyze heap memory," the memory footprint is discussed in terms of dirty and swapped pages, which count towards an application's memory footprint. Dirty pages are those that have been written to by the application, and if they are not used for a while, they can be swapped out to disk to manage memory pressure. The session also covers tools available in Xcode for analyzing and managing memory usage, such as the memory report and memory graph debugger, which help developers understand and optimize their application's memory footprint.

For more detailed information, you can refer to the session Analyze heap memory (00:00:50) which provides an overview of heap memory and tools for inspecting heap memory issues.