[jonstewart]

“It’s the memory, stupid!” So wrote Richard Sites, lead designer of the famous DEC Alpha chip, in 1996 (http://cva.stanford.edu/classes/cs99s/papers/architects_look...). It’s rung true for 30 years.

Where C application code often suffers, but by no means always, is the use of memory for data structures. A nice big chunk of static memory will make a function fast, but I’ve seen many C routines malloc memory, do a strcpy, compute a bit, and free it at the end, over and over, because there’s no convenient place to retain the state. There are no vectors, no hash maps, no crates.io and cargo to add a well-optimized data structure library.

It is for this reason I believe that Rust, and C++, have an advantage over C when it comes to writing fast code, because it’s much easier to drop in a good data structure. To a certain extent I think C++ has an advantage over Rust due to easier and better control over layout.

[JacoboJacobi]

I'd certainly agree that malloc is the Achilles heel of any real world C. Overall though C++ was not a particularly good solution to memory efficiency since having OO available made the situation look like a fast sprint to the cake shop.

[jonstewart]

Heavy smalltalk-style OOP in C++ has kind of died out, especially with data structures. So with any templated data structure you’re reducing indirection from vtables and you have the opportunity to allocate however you want, often in continuous slabs to ease memory transfer and caching.