As part of troubleshooting, I tried to install the RealTimelinux-rt-ltspackage, but it wasn’t found in the Extra repository…
sudo pacman -S linux-rt-lts
error: target not found: linux-rt-lts
I’ve looked into this problem on the Arch forums, but I don’t want to start messing around with Manjaro mirror settings for fear of defaulting farther upstream to Arch proper.
Is there something I should know or do about not being able to install from the Extra repositories?
Is there a reason this specific package should not be installed on Manjaro?
Indeed, there is no such package in the Manjaro repositories. However, there are several -rt kernels you can choose from…
linux61-rt (LTS)
linux66-rt (LTS)
linux67-rt (regular)
Also, installing kernels is best done through mhwd, or through the manjaro-settings-manager, not through pacman or pamac — you can do that, but then you have to manually create the initramfs for that kernel and update the boot loader.
Manjaro has its own kernels as mentioned by @Aragorn, it’s not recommendable to install pure Arch kernels on a Manjaro install. If this kernel is crutial for you think about using Arch.
So, it’s not available on Manjaro because it shouldn’t be installed, and so I was right to ask first—before messing with the mirrors as they did on upstream Arch forums.
But should I install any of those either?
I’m all starry-eyed from using the shiny-new 6.9 kernel with updated hardware support from the Arch kernel… Those 61 and 67 numbers scare me.
Then if I install one of these with mhwd -i linux61-rt, I’ll lose my 6.9 kernel glory? Are the RT kernels a slower dev stream then?
Well, that depends on what kind of glory you are getting from 6.9.
Unless you are on the very latest hardware for which there was no support yet in 6.1 and 6.6, you won’t be losing much. Furthermore, 6.1 and 6.6 are LTS kernels, so they will be supported with bug fixes until December 2026, whereas 6.9 is just a regular kernel and will surely become EOL in a few months.
Either way, installing any kernel version will not remove your current kernel. It’ll still be there, and by default, GRUB will either boot the kernel with the highest version, or — if you selected another one by way of the “Advanced Options” menu in GRUB — it’ll remember the last kernel you booted up into.
Yes, I just did that and rebooted. Everything works normally, which means the RealTime kernel did not fix the trouble I was up against with RealTime and ALSA, but that is a different question.
Now, we know it didn’t need to be done, but we tried the right way and the RealTime kernel didn’t fix it, even though the message was about RealTime.
rtcqs is a Python utility to analyze your system and detect possible bottlenecks that could have a negative impact on the performance of your system when working with Linux audio
rtcqs - version 0.6.2
Root User
=========
[ OK ] Not running as root.
Group Limits
============
[ OK ] User jc is member of a group that has sufficient rtprio (98) and memlock (unlimited) limits set.
CPU Frequency Scaling
=====================
[ WARNING ] The scaling governor of one or more CPUs is not set to 'performance'. You can set the scaling governor to 'performance' with 'cpupower frequency-set -g performance' or 'cpufreq-set -r -g performance' (Debian/Ubuntu). See also https://wiki.linuxaudio.org/wiki/system_configuration#cpu_frequency_scaling
Kernel Configuration
====================
[ OK ] Valid kernel configuration found.
High Resolution Timers
======================
[ OK ] High resolution timers are enabled.
Tickless Kernel
===============
[ OK ] System is using a tickless kernel.
Preempt RT
==========
[ WARNING ] Kernel 6.9.3-3-MANJARO without 'threadirqs' parameter or real-time capabilities found. See also https://wiki.linuxaudio.org/wiki/system_configuration#do_i_really_need_a_real-time_kernel
Spectre/Meltdown Mitigations
============================
[ WARNING ] Kernel with Spectre/Meltdown mitigations found. This could have a negative impact on the performance of your system. See also https://wiki.linuxaudio.org/wiki/system_configuration#disabling_spectre_and_meltdown_mitigations
RT Priorities
=============
[ OK ] Realtime priorities can be set.
Swappiness
==========
[ WARNING ] vm.swappiness is set to 60 which is too high. Set swappiness to a lower value by adding 'vm.swappiness=10' to /etc/sysctl.conf and run 'sysctl --system'. See also https://wiki.linuxaudio.org/wiki/system_configuration#sysctlconf
Filesystems
===========
[ OK ] The following mounts can be used for audio purposes: /
IRQs
====
[ OK ] Soundcard snd_hda_intel:card0 with IRQ 139 does not share its IRQ.
[ OK ] USB port xhci_hcd with IRQ 125 does not share its IRQ.
Power Management
================
[ OK ] Power management can be controlled from user space. This enables DAWs like Ardour and Reaper to set CPU DMA latency which could help prevent xruns.
Imma start dealing with these, but the CPU performance setting didn’t fix it before. Will look at others.
If the -rt kernel did not solve your problem, then perhaps better would be to start a new thread about that. This thread was specifically a question about the available real-time kernels in Manjaro, and that discussion has been had now.
