tuna? You really want to verify tuna?

[rlovell3]

PopOS 22.04LTS.
I edited /etc/tuned/realtime-virtual-host-variables.conf to isolate 4 cores like this:
isolated_cores=20-23

After changing the active profile to realtime-virtual-host, I ran the verification:
sudo tuned-adm verify
which produced

Verification failed, current system settings differ from the preset profile. You can mostly fix this by restarting the Tuned daemon, e.g.: systemctl restart tuned

which did not fix the error. It persisted through the restart.

cat /var/log/tuned/tuned.log:
ERROR tuned.plugins.plugin_script: script '/usr/lib/tuned/realtime/script.sh' error output: '/usr/lib/tuned/realtime/script.sh: line 14: tuna: command not found'

My first thought was, what? tuna? So I went and looked at the realtime/script.sh and sure enough, it says "verify() {tuna....".

I didn't have anything to do with the "realtime" profile. I only tweaked the "realtime-virtual-host-variables.conf" file.

For the record, I went back into the conf file and commented out my isolated_cores statement. I then went back and made "balanced" the active profile (which was the default before I even thought about changing anything). The restart and subsequent verify steps produced errors (on the purely default configuration). A look at the logs indicated that tuned is trying to manipulate my grub configuration, but hello: this machine doesn't use grub. Grub is not even installed, but your stuff doesn't even check to see if Grub is the bootloader. It just assumes...... It is also showing errors about various device hosts 'alpm' = 'None' expected 'medium_power'. There are a lot of those. In all, there are a lot of errors in the default configuration, and my one little change resulted in this new tuna adventure.

As it stands, the default tuned configuration never verifies as a success. It fails directly from the default settings, and then gets really funky about tuna when I try to follow the example in the /etc/tuned/realtime-virtual-host-variables.conf to isolate a few cores for when I spin up any virtual machines.

[adriaan42]

Based on your mention of PopOS 22.04LTS, I assume you have TuneD 2.15, which is almost four years old. In addition, back then the packaging and support for Debian (and Ubuntu) was not very good, especially when it comes to the realtime profiles...

As for tuna, that does not seem to be a dependency on Debian (https://salsa.debian.org/debian/tuned/-/blob/debian/unstable/debian/control), which is potentially a packaging bug there (@evgeni). But looking back in history it seems that tuna was used in the past for CPU isolation, and has been replaced by TuneD-internal features (scheduler plugin). The only remaining use is in this verification in the realtime profile, and seeing that the scheduler plugin should already do all necessary verification, I think that could probably just be removed, along with the dependency on the tuna package...