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I am using Ubuntu 14.04 in embedded

And I want to change Linux generic-kernel to Linux low-latency-kernel. But i think if i change the kernel, some programs already installed and devices(for example touch pad) may not work, and i have to build and re-install.

Current My Linux version is 3.10.17, So How about changing to low-latency-kernel which is same version(3.10).

It could also have some side effect?

And additionally, is there any command to upgrade kernel to low-latency-kernel, like apt-get....

Actually i found 'deb' file to upgrade kernel to low-latency for version 3.16 but i couldn't find 3.10.

marked as duplicate by Panther, kiri, karel, Eric Carvalho, Eliah Kagan Apr 27 '15 at 22:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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The low latency kernel is not needed by most people as of kernel 2.6.31 .

It is (was) used as far as I know mainly for audio recording, although there may have been other uses. It is difficult to find detailed discussions on the patch but I suggest you look at

Kernels >= 2.6.31 seem to work pretty good without RT patch, also for real-time pro audio usage. It's not strictly necessary anymore to install a real-time ('rt') kernel to get good results. Although the best results are still expected when using a real-time kernel. Try it, test it and decide for yourself.

http://wiki.linuxaudio.org/wiki/system_configuration#the_kernel

NOTE: From this link they are discussing audio and "good" and "best" are extremely subjective and sometimes they are measuring things in very small time units and all the measurements on the web are old, pre 2.6.31 kernel.

Some confusion persists about the purposes of -lowlatency and -realtime kernels.

The goal of -realtime and -rt (hard real-time) kernels is to achieve the lowest possible latency at every cost. In technical slang "hard realtime systems should always meet their deadlines". Thus developers should use the most advanced programming techniques (sleeping spinlocks, PI Mutex, Full preemption, IRQ Threads and others) and sacrifice things like reliability, power-saving and throughput.

https://help.ubuntu.com/community/UbuntuStudio/RealTimeKernel

Fedora also has some quality documentation on this issue

https://docs.fedoraproject.org/en-US/Fedora/17/html/Musicians_Guide/sect-Musicians_Guide-Real_Time_Linux_Kernel.html

https://docs.fedoraproject.org/en-US/Fedora/15/html/Musicians_Guide/chap-Musicians_Guide-Real_Time_and_Low_Latency.html

Note the fedora links are somewhat dated and Fedora no longer maintains low latency kernels.

So a better question is, what makes you think a real time kernel is going to help you ? It does not appear you are doing anything (such as audio recording) that requires a RT kernel and the RT patch is unlikely to solve your problems with embedding.

You can always try a low latency kernel and if you have problems switch back, install and remove them with apt-get

sudo apt-get install linux-lowlatency

sudo apt-get remove linux-lowlatency

Personally I have not had any problems with the low latency kernel patch, but did not see any advantage either (I have used for audio recording only, Ardour 3 with multiple track play back, monitoring via headphones, and recording a new track).

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That is the linux-lowlatency package from standard Ubuntu repository. Should not affect any software (I mean it won't need explicit recompile and adaptation).

But investigate some other options if you have time: the cgroups feature of the linux kernel can provide finer control without customizing kernel binaries.

  • Your comments are very valuable to us. So, leave them. – Velkan Apr 26 '15 at 13:24
  • The low latency kernel is is not necessary for most people. See wiki.linuxaudio.org/wiki/system_configuration#the_kernel and vhttps://help.ubuntu.com/community/UbuntuStudio/RealTimeKernel – Panther Apr 26 '15 at 13:35
  • That's okay. I thought you had something about cgroups. – Velkan Apr 26 '15 at 13:42
  • It depends on what you are doing, I am not sure how you would use cgroups here. I also advise at lease some discussion before installing the low latency kernel. Discussions on the low latency patch sometimes are more opinionated (IMO) then technical and the patch sacrifices stability and possibly security. I would advise the patch to someone who has a use for it (audio recording) but probably not on a standard desktop or server. – Panther Apr 26 '15 at 13:51
  • Also, while fast, the actual latency with a low latency kernel is more variable, the latency is not constant. With a standard kernel, the latency, although longer, the latency is more constant. It is sometimes easier to compensate for a longer, but predictable latency then a faster by unpredictable latency. One can never make the latency 0 ;) For these reasons most people are going with a standard kernel. Most peole can not detect the difference between 1 ms and 1.1 ms ;) – Panther Apr 26 '15 at 13:56

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