Comment by nixosbestos
Comment by nixosbestos 10 months ago
Wait, so should casual desktop Linux users try this out too? I assumed there must be some trade-off to using RT?
Comment by nixosbestos 10 months ago
Wait, so should casual desktop Linux users try this out too? I assumed there must be some trade-off to using RT?
> It's every so slightly slower
in what way? I'd say responsiveness is more important to the desktop than raw performance and from my experience with nearly 2 decades of using Linux desktops, responsiveness has never been great.
If I'm switching between windows whilst encoding a video in the background, the window manager should have instant priority even if it means starving the background task of some CPU time. on GNOME this is quite bad, run a very heavy task (e.g. AI) in the background and the desktop will start to suffer.
I doubt that RT makes a nicer user experience on desktops. You are probably better of switching to another desktop-oriented scheduler.
Not really any harm in trying, but definitely note that the trail marked “trying scheduler changes to see if it improves desktop performance” is strewn with skeletons, the ghosts thereof haunt audio forums sayings things like “[ghostly] oooooohhhh, the sound is so much clearer now that I put vibration dampeners under my usb audio interface”.
The reason I wrote my original comment is precisely because “audio xruns at a higher latency with lower system load” is a very concrete measure of improvement that I can't fool myself about, including effects like “the system runs better when freshly booted for a while” that otherwise bias the judgements of the uninitiated towards “…and therefore the new kernel improved things!”
There isn't much on a desktop that is sensitive to latency spikes on the order of a couple ms, which a stock kernel should already be able to maintain.
Perhaps that's a theory.
In reality, my desktop does-everything Linux rig literally does everything. It's my ZFS file server/NAS, and VM host, and web-browsing machine, and gaming box, and it does everything else I do with a computer at home (except for routing, directly controlling 3D printers, and playing movies on the BFT).
Sometimes, especially when gaming, sound glitches. It's annoying to me when this happens. (It'd be far worse than annoying if I were doing serious audio work, but I am not.)
An RT kernel may help with that. Not by automagically adjusting buffers (or whatevers) for a glitch after it happens, but by preventing it from ever happening to begin with.
(And I intend to find out for sure if I ever get far enough into moving into this new place that I can plug my desktop back in, now that it is a mainlined feature instead of a potential rabbit hole.)
That's a different knob that can be used; Increasing buffer size simply is a different compromise to achieve the result of meeting audio deadlines.
Quality vs latency, pick one.
Or just use PREEMPT_RT to tighten the timings for the critical audio worker getting the cpu ;)
It's every so slightly slower, but the difference is negligible and won't be noticed on a desktop machine. These days, I just run the (Debian) real-time kernel as a matter of course on my everyday machine.
I haven't objectively tested it, but my feeling is that it actually makes for a nicer user experience. Sometimes Gnome can briefly freeze or feel sluggish (presumably the CPU is off doing something) and I feel that the RT kernel does away with this. It could be a placebo effect though.