this post was submitted on 18 Jun 2024
143 points (96.1% liked)

Linux

5334 readers
192 users here now

A community for everything relating to the linux operating system

Also check out [email protected]

Original icon base courtesy of [email protected] and The GIMP

founded 1 year ago
MODERATORS
 

One big difference that I've noticed between Windows and Linux is that Windows does a much better job ensuring that the system stays responsive even under heavy load.

For instance, I often need to compile Rust code. Anyone who writes Rust knows that the Rust compiler is very good at using all your cores and all the CPU time it can get its hands on (which is good, you want it to compile as fast as possible after all). But that means that for a time while my Rust code is compiling, I will be maxing out all my CPU cores at 100% usage.

When this happens on Windows, I've never really noticed. I can use my web browser or my code editor just fine while the code compiles, so I've never really thought about it.

However, on Linux when all my cores reach 100%, I start to notice it. It seems like every window I have open starts to lag and I get stuttering as the programs struggle to get a little bit of CPU that's left. My web browser starts lagging with whole seconds of no response and my editor behaves the same. Even my KDE Plasma desktop environment starts lagging.

I suppose Windows must be doing something clever to somehow prioritize user-facing GUI applications even in the face of extreme CPU starvation, while Linux doesn't seem to do a similar thing (or doesn't do it as well).

Is this an inherent problem of Linux at the moment or can I do something to improve this? I'm on Kubuntu 24.04 if it matters. Also, I don't believe it is a memory or I/O problem as my memory is sitting at around 60% usage when it happens with 0% swap usage, while my CPU sits at basically 100% on all cores. I've also tried disabling swap and it doesn't seem to make a difference.

EDIT: Tried nice -n +19, still lags my other programs.

EDIT 2: Tried installing the Liquorix kernel, which is supposedly better for this kinda thing. I dunno if it's placebo but stuff feels a bit snappier now? My mouse feels more responsive. Again, dunno if it's placebo. But anyways, I tried compiling again and it still lags my other stuff.

(page 3) 28 comments
sorted by: hot top controversial new old
[–] [email protected] 1 points 5 months ago

Hmm, I can't say that I've ever noticed this. I have a 3950x 16-core CPU and I often do video re-encoding with ffmpeg on all cores, and occasionally compile software on all cores too. I don't notice it in the GUI's responsiveness at all.

Are you absolutely sure it's not I/O related? A compile is usually doing a lot of random IO as well. What kind of drive are you running this on? Is it the same drive as your home directory is on?

Way back when I still had a much weaker 4-core CPU I had issues with window and mouse lagging when running certain heavy jobs as well, and it turned out that using ionice helped me a lot more than using nice.

I also remember that fairly recently there was a KDE/plasma stutter bug due to it reading from ~/.cache constantly. Brodie Robertson talked about it: https://www.youtube.com/watch?v=sCoioLCT5_o

[–] [email protected] 1 points 5 months ago (2 children)
[–] agilob 0 points 5 months ago

The CPU is already 100% busy, so changing number of compilation jobs won't help, CPU can't go faster than 100%.

load more comments (1 replies)
[–] agilob 1 points 5 months ago* (last edited 5 months ago)

EDIT: Tried nice -n +19, still lags my other programs.

yea, this is wrong way of doing things. You should have better results with CPU-pinning. Increasing priority for YOUR threads that interact all the time with disk io, memory caches and display IO is the wrong end of the stick. You still need to display compilation progress, warnings, access IO.

There's no way of knowing why your system is so slow without profiling it first. Taking any advice from here or elsewhere without telling us first what your machine is doing is missing the point. You need to find out what the problem is and report it at the source.

[–] [email protected] -1 points 5 months ago (5 children)

Yeah I think the philosophy of Linux is to not assume what you are going to be use it for. Why should Linux know where your priorities are better than you?

Some people want to run their rustc, ffmpeg or whatever intensive program and don't mind getting a coffee while that happens, or it's running on a non-user facing server anyway, to ensure that the process happens as soon as technically possible. Mind you that your case is not an "average usecase" either, not everyone is a developer that does compilation tasks.

So you've got a point that the defaults could be improved for the desktop software developer user or somehow made more easily configurable. As suggested downthread, try the nice command, an optimized scheduler or kernel, or pick a distribution equipped with that kind of kernel by default. The beauty of Linux is that there are many ways to solve a problem, and with varying levels of effort you can get things to pretty much exactly where you want them, rather than some crowdpleasing default.

load more comments (5 replies)
[–] [email protected] -2 points 5 months ago

Ha, that's funny. When I run some Visual Studio builds on Windows it completely freezes at times.

Never have that issue on EOS with KDE.

[–] FizzyOrange -3 points 5 months ago (3 children)

No. And even worse is Linux's OOM behaviour - 99% of the time it just reboots the machine! Yes I have swap and zswap.

Linux is just really bad at desktop.

load more comments (3 replies)
load more comments
view more: ‹ prev next ›