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I have installed a low latency kernel to help Ardour's performance while recording audio. On boot-up, it appears I can select which 'version' of Ubuntu I want; the two choices are 'Ubuntu' and 'Ubuntu low-latency'. However, when I run uname -r with either one, I get 3.14.0-031400-lowlatency.

Why the separate boot up options if 'Ubuntu' is the same as 'Ubuntu low-latency'? Is there a way to actually boot-up with the generic kernel? Is there a reason to, or are there drawbacks from using the low latency kernel while doing my day-to-day tasks?

Martin Thornton
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Cameron Sima
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  • You have to reboot to switch. With modern CPU, however, it is rare you need a low latency kernel. At any rate, it sounds as if your grub is not configured to boot the correct kernel. There is a nice discussion here - http://askubuntu.com/questions/126664/why-to-choose-low-latency-kernel-over-generic-or-realtime-ones – Panther Oct 20 '15 at 16:12
  • I am rebooting, but it appears no matter which one I select, it loads the low latency one regardless – Cameron Sima Oct 20 '15 at 16:14
  • If you do not need it, remove it. If you wish to keep it, configure grub, manually, to boot the correct kernel. https://help.ubuntu.com/community/Grub2 – Panther Oct 20 '15 at 16:25
  • For anyone who upgraded to Artiful 17.10 and landing here first from a search, see bug 1728760. – Jesse Glick Nov 16 '17 at 16:05

2 Answers2

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Here is a nice fix with dual listing:

  • Low-latency

    1. Download ubuntustudio-default-settings package from http://packages.ubuntu.com/trusty/ubuntustudio-default-settings (choose your release through links in the top right corner)
    2. Extract it.

    3. Copy 09_lowlatency file to /etc/grub.d/

      If you don't want low-latency entry to be the top one, rename it to 11_lowlatency so it will be processed after 10_linux.

  • Generic and other kernel types

    Edit /etc/grub.d/10_linux as explained in this answer to exclude low-latency kernel from its listing.

user.dz
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The answer by Sneetsher is valid, but, just as an alternative, I used a different solution. If you want to have separate entries in GRUB in /etc/grub.d/ for generic and lowlatency kernels, you can just make a copy of the file 09_lowlatency. If you want the new entry to be the first one, name it something like 08_generic, but you can choose the ordering as you prefer (e.g. you can have 08_lowlatency and 09_generic). Then, edit the copied file and replace all the occurrences of lowlatency with generic, and update GRUB. That should give you the two options on boot.

javidcf
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