/var/log/dmesg has this message;

Unknown kernel command line parameters "BOOT_IMAGE=/boot/vmlinuz-5.19.15", will be passed to user space.

Here's the kernel line in dmesg; (Not sure what unknown parameter it's talking about?)

Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.19.15 root=UUID=9c5dee78-fbf7-4d53-809e-2df4cbedeb1f ro rootfstype=ext4 scsi_mod.use_blk_mq=1 dm_mod.use_blk_mq=y tsc=unstable trace_clock=local

I'm using BFQ, wondering if I should continue using for it?
scsi_mod.use_blk_mq=1 dm_mod.use_blk_mq=y

Also been wondering if I should just go with MQ now, hmm... :/

Also, wondering if I should still use tsc and trace_clock?

It just told you.

The message is purely informational: it's not an error. Bootloaders have a tendency to pass additional information through. Also, any parameters for your initrd will likely show up.
e.g. from my custom initrd:

2 members found this post helpful.

It is talking about BOOT_IMAGE which is not among the kernel parameters described in
/usr/src/linux/Documentation/kernel-parameters.txt

Even though the kernel does not know what to do with that parameter it allows kernel unknown parameters which might be usable for things like startup scripts or boot loaders. Such userspace programs can study all parameters in /proc/cmdline .

This message is nothing to worry about.

regards Henrik

2 members found this post helpful.

Ahh ok thanks