How to further decrease Lazer input latency in Linux?

[ominoussage]

Even after playing on Lazer exclusively for about 3 years now, I still vividly remember how instant and responsive Stable was before I switched to Lazer and I'm certain Lazer still hasn't reached that level of responsiveness. I feel like Lazer's input latency is still higher than stable, even as of now.

Good thing on Windows (Windows 10, at least), you can install REAL which does most of the work for you. But on Linux, extra configurations are needed to achieve ultra low latency. There are guides on how to achieve ultra low latency on stable but I haven't seen any for Lazer on any platform.

Can anyone come up with solutions/guides for Linux? Any help would be appreciated.

[sineplusx]

Do you want to reduce input latency or audio latency? (you mentioned REAL, which only does stuff with audio)

By my definition "input latency" is the time it takes for a physical input to be registered ingame, but does NOT include the time to render and display stuff on screen. This type of latency is hard to decrease unless you get better hardware, and should not make a difference between Linux and Windows. When most players talk about "input latency" they actually mean things being sluggish on screen, but that is mostly visual latency (game processing, rendering and display).

For reducing audio latency, I have a low-latency audio setup for PipeWire that I can share. It's in no way perfect, but it reduces audio latency by quite a bit.

[Stoppedpuma]

For audio you're able to change the alsa buffer as @sineplusx stated above, using standard buffer sizes you are able to change the audio latency, just make sure your period doesn't go out of bounds or your game will either slow down, not play audio, or even not open at all. Here's an example launch command using PipeWire:
PIPEWIRE_ALSA='{ alsa.buffer-bytes=1024 alsa.period-bytes=128 }' /path/to/osu/appimage

[rszyma]

There's also another an env variable to tweak: PIPEWIRE_QUANTUM. In my case I set it to PIPEWIRE_QUANTUM=64/44100 to elliminate glitchy audio.

Some notes/tips:

• the above only work for "PipeWire Sound Server" audio output in osu settings (which for me is also "Default")
• setting buffer-bytes to 1024 (or less) didn't work for me at all, but 2048 works well.
• you can use pw-top command to check audio buffer sizes changed

[Stoppedpuma]

PIPEWIRE_LATENCY, PIPEWIRE_QUANTUM, PIPEWIRE_RATE

These options don't do anything as the audio engine osu! uses (BASS) only has support for alsa, proper pipewire server support will come with SDL3 audio backend.

you can use pw-top command to check if settings applied.

Invalid, see above.

setting buffer-bytes to 1024 (or less) didn't work for me at all, but 2024 works well.

I should have mentioned this varies system to system

[rszyma]

Sorry for spreading misinformation, I forgot to mention that probably most of these settings don't even apply. I just checked which from what I menationed are actually doing anything, and edited my above comment appropriately.

PIPEWIRE_LATENCY, PIPEWIRE_QUANTUM, PIPEWIRE_RATE

These options don't do anything

That's not entirely true. Setting PIPEWIRE_QUANTUM does make difference (see my edited comment above), but agree on PIPEWIRE_LATENCY and PIPEWIRE_RATE - it seems to not apply indeed.

the audio engine osu! uses (BASS) only has support for alsa, proper pipewire server support will come with SDL3 audio backend

Yes it's true but pipewire it also has compatibility layer with apps that use alsa. But nevertheless the options PIPEWIRE_QUANTUM and PIPEWIRE_ALSA are pipewire env variables.

you can use pw-top command to check if settings applied.

Invalid, see above.

?? No idea what kind of audio setup you have, but for me, changing either PIPEWIRE_QUANTUM or PIPEWIRE_ALSA changes the values shown by pw-top.

[Stoppedpuma]

The pw-top comment was meant about the value shown when using PIPEWIRE_LATENCY and PIPEWIRE_RATE. For PIPEWIRE_ALSA it's fine.

The "glitchy audio" you're talking about should be fixed by increasing your period size to 128 or 256.

Yes it's true but pipewire it also has compatibility layer with apps that use alsa.

I'm aware, this was bad wording on my part. To better explain, those options don't affect the alsa module which osu! reads, only the pipewire server and pipewire-pulse modules which osu! can't.

[okolenmi]

It looks like I have near zero latency without using it (hits are near the center with 0 offset on average) on Ubuntu 24.04.1 LTS. With it I have to change my offset to -9 to feel comfortable. So it's better to not use it, if you have no problems with average hit error. Also I have better fps and less input lag in Ubuntu, so it's the perfect OS for this game without any changes.