raqote VS cargo-asm

There's several different approaches you could take, but I'd probably suggest macroquad as the easiest. I've also used minifb for windowing + a drawing library like raqote or tiny-skia.

You may specify font family by adding a line font = "Source Sans Pro" into a config file (path is $HOME/.config/yofi/yofi.config). Though, perhaps you meant "Source Code Pro" which is unfortunately broken in third-party rendering library. You may specify font size similarly with font_size = 12 line, though the binary from the last release doesn't support it yet, so you either may built yofi from master (as simple as cargo b --release), or wait for the next release (I think it will be on this week).

cargo asm might be useful here (if you can't use godbolt).

They should be inlined in release mode. You'd have to verify by checking the assembly, though, which could be done directly in the Rust playground or with a tool like cargo-asm.

You can use cargo asm - not sure if you can integrate it with VSCode, but even from a terminal it's a pretty convenient tool.

There's probably a built-in one somewhere, but I suspect it'd be easier just to install https://github.com/gnzlbg/cargo-asm

I don't know if there's a way to do a side by side comparison but cargo-asm uses the source mapping information from rustc to annotate chunks of assembly with it's respective rust code, though it's an imperfect process.

After that you would need some tools to help figure out how to achieve improvements. That will depend on your system and personal preferences. As the other commenter suggested, perf is a good choice on linux. I personally like to look at the generated assembly, using either cargo asm, godbolt, or just rust playground.

Doesn't this already exist? https://github.com/gnzlbg/cargo-asm

From the flamegraph, we knew which function was taking the majority of the time, which we briefly described above. We started by looking at the assembly code it generated to see if there were any opportunities to make it faster. We did this with cargo-asm.

You're best bet at the moment is probably using cargo-asm to inspect the function assembly to see when it is performing the correct TCO.