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Thread: The Free Studio Project - part 4 Performance improval and Low Latency

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    Default The Free Studio Project - part 4 Performance improval and Low Latency


    Warning !
    If you have an NVidia based graphics card you should know from my previous article that you should NOT install the official drivers from NVidia (IF you install the Realtime Kernel)
    Fortunately linux has the so-called "nouveau" drivers that provide good support for NVidia cards

    The problem with the Nouveau drivers crashing a system with RealTime kernel, so you don't need to follow the next instructions (in red) anymore

    As for Official NVidia drivers, NVidia is not planning on supporting RT kernels in the near future. The reason for this is that the Realtime patch is not considered "Official" and NVidia will only support Official kernels.


    BUT the nouveau drivers will also crash (freeze) the system when used together with the RT kernel.


    To solve this problem we're going to disable the acceleration in GRUB to prevent this problem

    so before we're going to do anything else, we are going to edit GRUB.

    what you see in bold and italic is what you need to type in a terminal window or a config-file in most cases you can copy & paste.

    - open a terminal window (if you upgraded to Jessie you can move the mouse pointer to the top left of the screen and you should see a "favorites" list and a search box.
    - type : terminal in this box and click the black terminal icon
    - type : sudo gedit /etc/default/grub
    - add the following : GRUB_CMDLINE_LINUX_DEFAULT="quiet nouveau.noaccel=1"
    - Save and close gedit
    - type : update-grub

    reboot your computer


    Now let's start with the actual performance settings.
    - Download my custom kernel image (Realtime, 1000Hz and tickless) (download to $HOME/Downloads but that should be the default location).


    in general we say that unless you have problems with your old kernel there is no real need to upgrade to a newer one.
    However I did notice that my 3.x kernel is older than the "stock" kernel that comes with Debian 8.0 and as a result GRUB will boot that kernel (which is not a Realtime kernel) by default.

    So unless you select the RT kernel during every boot the stock one will be used which might not work best. (you can check your kernel version from a terminal window by typing "uname -a")

    Installing my 4.4.7 kernel should be automatically set as the default kernel.

    - open a new terminal window
    - browse to your Download folder : cd /home/USERNAME/Downloads (remember that Linux is CaSe SenSitive and also there is a shortcut for typing longer names, you can use the <TAB> key to autocomplete.


    - install the file by typing : sudo dpkg -i *.deb
    - if you get an error message type : sudo apt-get -f install

    - Reboot your system.

    Kernel upgraded to 4.6.0

    Recently Linux released the new 4.6 kernel as stable build, this kernel introduces some major performance enhancements for certain systems.
    I recently patched and compiled this kernel and you can now install it on your system (if you want).

    to make installations easier I've setup a repository (Genfury provides free public repositories for various systems including APT). so what do you need to do to get my new kernel installed ?

    Follow the following steps :

    1. open a terminal
    2. enter the command : sudo gedit /etc/apt/sources.list
    3. enter your root password (that's the Administrator for the Windows converts)
    4. in the text editor go to the bottom and add the following 2 lines :
    Code:
    #CloudyWizzard Realtime Kernels
    deb [trusted=yes] https://repo.fury.io/cloudywizzard/ /
    5. save and close the text editor
    6. enter the command : sudo apt-get update && sudo apt-get install linux-headers-4.6.0-rt1tickless && sudo apt-get install linux-image-4.6.0-rt1tickless
    7. when asked enter the root password, but it should not be needed.
    8. If you get no error messages the new Kernel is installed and you can reboot the system to start using it.
    9. if you want to check the current kernel you are using, you can do this by opening a terminal and typing : "uname -a" and it should reply with something like this :

    Linux Debian-Mobile 4.6.0-rt1tickless #1 SMP PREEMPT RT Sun Jun 5 18:21:37 CEST 2016 x86_64 GNU/Linux


    - now let's install a script that will check if all needed conditions are met (the answer is no, but I'm installing it in advance).
    - Download the script.
    - open a terminal window and go to your download folder
    - make a new folder for the script : mkdir rtscan
    - copy the script into this folder : cp realtimeconfigquickscan.tar.xz rtscan/. (don't forget the DOT at the end !)
    - go into the folder : cd rtscan
    - execute the script : ./realTimeConfigQuickScan.pl (this will tell you what you have done and need to do, again don't forget the DOT at the beginning this time and the /)

    now some quick edits :

    sudo gedit /etc/rc.local
    add /sbin/sysctl -w vm.swappiness=10

    sudo gedit /etc/sysctl.conf
    add fs.inotify.max_user_watches = 524288


    sudo echo 'KERNEL=="hpet", GROUP="audio"' | sudo tee /etc/udev/rules.d/40-hpet-permissions.rules

    sudo echo 'KERNEL=="rtc0", GROUP="audio"' | sudo tee /etc/udev/rules.d/40-hpet-permissions.rules

    sudo echo -n performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
    sudo echo -n performance > /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

    now reboot your system and run the realtime check script again.
    You should see good for everything except at the bottom (a message about tmpfs) "
    ** Warning: no tmpfs partition mounted on /tmp but you can ignore this

    if you still get messages that some things are not setup correctly reply and I'll look into it (maybe I forgot something).

    The next tutorial will be about installing Ardour and setting-up Jack.

    Last edited by Patrick; 06-10-2016 at 02:01 PM.
    Fender 2012 American Standard Precision Bass (Left-handed)
    Fender '59 Bassman LTD.









  2. #2

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    Thanks for these articles, Patrick. The members love them!


    - low life -

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