[qwerty456127]

> ARMv7 and later, which come with graphics chips optimized for for something different than what X was built for

Are they SO slow on the tasks they are not optimized for they can't even beat a 25-year-old GPU like S3 Trio?

> I'd imagine that running a current distro with a current X WM wouldn't be a great experience on 90s machines.

Why does it have to be? What do we get for this cost? The only things in which I would find a modern Linux better than a 90s Linux are full UTF-8 support, modern crypto and hardware drivers availability.

> The difference will widen as Vulkan

I don't know a single person (among many dozens of Linux users I personally know) who would need it. I can only imagine movie makers using Blender or something like that

[Seirdy]

> Why does it have to be? What do we get for this cost? The only things in which I would find a modern Linux better than a 90s Linux are full UTF-8 support, modern crypto and hardware drivers availability.

A lot of exploit mitigations, especially spectre/meltdown mitigations, allocator hardening, auditd, toolchain hardening flags that introduce runtime checks, syscall filtering, etc. have introduced major slowdowns. I'm sure this isn't the only reason, but it's the only reason I am familiar with. Ask someone familiar with a different sector of osdev and they'd probably rattle off a few more.

I have noticed that lots of tasks that would be fast a decade or two ago are slow today on a rbpi: tasks like switching workspaces, switching browser tabs, etc. have noticeable delays. Sway makes switching workspaces and some window management functionality nearly instant in comparison. I've compared it with i3 and openbox; others have compared it with dwm. I'll see if I can find a link.

A lot of tasks become faster with GPU acceleration, which is why OpenGL and Vulkan accel are helpful.

[vidarh]

> Sway makes switching workspaces and some window management functionality nearly instant in comparison. I've compared it with i3 and openbox; others have compared it with dwm. I'll see if I can find a link.

i3/dwm (or any X window manager), unlike Sway (or any Wayland compositor) has nothing to do with client window contents rendering. X and Wayland works fundamentally differently in that respect. Under Wayland the compositor and wm is the same. Under X the server and wm are separate programs in separate processes, and the latter is not involved in rendering the client window contents, only the window chrome, if any.

[qwerty456127]

I see. Quite a reasonable, detailed explanation, thank you. I didn't notice any visible difference in perceived performance (just using the PC to write code, browse the web and watch videos) when I switched spectre/meltdown mitigations on/off on my old Core 2 Duo PC though. It just always worked perfectly fast.

Meanwhile, I often don't need any network connection (when coding, watching pre-download videos, or running data/number-crunching or build scripts). Can I expect 90s-like efficiency if I disable all the mitigations and hardening stuff?

[Seirdy]

There are...a lot of good reasons to keep the mitigations enabled. All nontrivial software has bugs, and hardening measures can keep some of the worst ones in check. Frankly, the Linux desktop needs more of this, not less.

That being said, one writeup explained how disabling several mitigations improved http server perf by several factors: https://talawah.io/blog/extreme-http-performance-tuning-one-...