nixos/gnome3: add realtime-scheduling option

This adds an option services.gnome3.experimental-features.realtime-scheduling
See this comment for the motivation [0].
Having gnome-shell launched with capability seemed harmless at first,
but it caused these issues [1] [2] for people who aren't even using
the feature. It makes more sense to make this optional.

[0]: https://github.com/NixOS/nixpkgs/issues/90201#issuecomment-683304279
[1]: https://github.com/NixOS/nixpkgs/issues/90201
[2]: https://github.com/NixOS/nixpkgs/issues/86730
This commit is contained in:
WORLDofPEACE 2020-10-06 01:58:51 -04:00
parent 89281dd1df
commit 656cd70ea8

View File

@ -68,6 +68,38 @@ in
core-shell.enable = mkEnableOption "GNOME Shell services";
core-utilities.enable = mkEnableOption "GNOME core utilities";
games.enable = mkEnableOption "GNOME games";
experimental-features = {
realtime-scheduling = mkOption {
type = types.bool;
default = false;
description = ''
Makes mutter (which propagates to gnome-shell) request a low priority real-time
scheduling which is only available on the wayland session.
To enable this experimental feature it requires a restart of the compositor.
Note that enabling this option only enables the <emphasis>capability</emphasis>
for realtime-scheduling to be used. It doesn't automatically set the gsetting
so that mutter actually uses realtime-scheduling. This would require adding <literal>
rt-scheduler</literal> to <literal>/org/gnome/mutter/experimental-features</literal>
with dconf-editor. You cannot use extraGSettingsOverrides because that will only
change the default value of the setting.
Please be aware of these known issues with the feature in nixos:
<itemizedlist>
<listitem>
<para>
<link xlink:href="https://github.com/NixOS/nixpkgs/issues/90201">NixOS/nixpkgs#90201</link>
</para>
</listitem>
<listitem>
<para>
<link xlink:href="https://github.com/NixOS/nixpkgs/issues/86730">NixOS/nixpkgs#86730</link>
</para>
</listitem>
</itemizedlist>
'';
};
};
};
services.xserver.desktopManager.gnome3 = {
@ -289,26 +321,6 @@ in
source-sans-pro
];
## Enable soft realtime scheduling, only supported on wayland ##
security.wrappers.".gnome-shell-wrapped" = {
source = "${pkgs.gnome3.gnome-shell}/bin/.gnome-shell-wrapped";
capabilities = "cap_sys_nice=ep";
};
systemd.user.services.gnome-shell-wayland = let
gnomeShellRT = with pkgs.gnome3; pkgs.runCommand "gnome-shell-rt" {} ''
mkdir -p $out/bin/
cp ${gnome-shell}/bin/gnome-shell $out/bin
sed -i "s@${gnome-shell}/bin/@${config.security.wrapperDir}/@" $out/bin/gnome-shell
'';
in {
# Note we need to clear ExecStart before overriding it
serviceConfig.ExecStart = ["" "${gnomeShellRT}/bin/gnome-shell"];
# Do not use the default environment, it provides a broken PATH
environment = mkForce {};
};
# Adapt from https://gitlab.gnome.org/GNOME/gnome-build-meta/blob/gnome-3-36/elements/core/meta-gnome-core-shell.bst
environment.systemPackages = with pkgs.gnome3; [
adwaita-icon-theme
@ -333,6 +345,27 @@ in
];
})
# Enable soft realtime scheduling, only supported on wayland
(mkIf serviceCfg.experimental-features.realtime-scheduling {
security.wrappers.".gnome-shell-wrapped" = {
source = "${pkgs.gnome3.gnome-shell}/bin/.gnome-shell-wrapped";
capabilities = "cap_sys_nice=ep";
};
systemd.user.services.gnome-shell-wayland = let
gnomeShellRT = with pkgs.gnome3; pkgs.runCommand "gnome-shell-rt" {} ''
mkdir -p $out/bin/
cp ${gnome-shell}/bin/gnome-shell $out/bin
sed -i "s@${gnome-shell}/bin/@${config.security.wrapperDir}/@" $out/bin/gnome-shell
'';
in {
# Note we need to clear ExecStart before overriding it
serviceConfig.ExecStart = ["" "${gnomeShellRT}/bin/gnome-shell"];
# Do not use the default environment, it provides a broken PATH
environment = mkForce {};
};
})
# Adapt from https://gitlab.gnome.org/GNOME/gnome-build-meta/blob/gnome-3-36/elements/core/meta-gnome-core-utilities.bst
(mkIf serviceCfg.core-utilities.enable {
environment.systemPackages = (with pkgs.gnome3; removePackagesByName [