I think a lot of modern software is bloated. I remember when GUI programs used to fit on a floppy or two. Nowdays we have bloated electron programs taking hundreds of MB of RAM just to show a simple text editor, because it drags a whole browser with it.

I love snappy software, and while I don't think we need to go back to programs fitting on a single floppy and using hundreds of KB of RAM, the pendulum does need to swing back a fair bit. I rewrote some CLI programs in the last few years that I found slow (one my own previously written in Python, the other written in C++ but not properly designed for speed). I used Rust, which sure helped compared to Python, but the real key was thinking carefully about the data structures used up front and designing for performance. And lots of profiling and benchmarking as I went along.

The results? The python program was sped up by 50x, the C++ program by 320x. In both cases it changed these from "irritating delay" to "functionally instant for human perception".

The two programs:

• Python to Rust: https://github.com/VorpalBlade/chezmoi_modify_manager
• Blog about rewriting the C++ program in Rust: https://vorpal.se/posts/2025/mar/25/filkoll-the-fastest-command-not-found-handler/

And I also rewrote a program I used to manage Arch Linux configs (written in bash) in Rust. I also added features I wanted so it was never directly comparable (and I don't have numbers), but it made "apply configs to system" take seconds instead of minutes, with several additional features as well. (https://github.com/VorpalBlade/paketkoll/tree/main/crates/konfigkoll)

Oh and want a faster way to check file integrity vs the package manager on your Linux distro? Did that too.

Now what was the point I was making again? Maybe I'm just sensitive to slow software. I disable all animations in GUIs after all, all those milliseconds of waiting adds up over the years. Computers are amazingly fast these days, we shouldn't make them slower than they have to be. So I think far more software should count as performance critical. Anything a human has to wait for should be.

Faster software is more efficient as well, using less electricity, making your phone/laptop battery last longer (since the CPU can go back to sleep sooner). And saves you money in the cloud. Imagine if you could save 30-50% on your cloud bill by renting fewer resources? Over the last few years I have seen multiple reports of this happening when companies rewrite in Rust (C++ would also do this, but why would you want to move to C++ these days?). And hyperscalers save millions in electricity by optimising their logging library by just a few percent.

Most modern software on modern CPUs is bottlenecked on memory bandwidth, so it makes sense to spend effort on data representation. Sure start with some basic profiling to find obvious stupid things (all non-trivial software that hasn't been optimised has stupid things), but once you exhausted that, you need to look at memory layout.

(My dayjob involves hard realtime embedded software. No, I swear that is unrelated to this.)

I don't mean this in a bad way; did an AI write this comment?