A daemon for X11 designed to automatically limit FPS or CPU usage of unfocused windows and run commands on focus and unfocus events.
- Dependencies
- Installation
- Usage
- Configuration
- Variables
- Tips and tricks
- Possible questions
- How does daemon work?
- Does that daemon reduce performance?
- Is it safe?
- Should I trust you and this utility?
- With which DE/WM/GPU daemon works correctly?
- Is not running commands on focus and unfocus makes system vulnerable?
- Can I get banned in a game because of this daemon?
- Why was that daemon developed?
- Bugs?
- Why is code so complicated?
- Gamescope which allows limit FPS on unfocus exists, Wayland becomes more popular. Are you not late by any chance?
- What about Wayland support?
- Why did you write it in Bash?
Required: bash util-linux cpulimit coreutils xorg-xprop xorg-xwininfo
Optional: mangohud lib32-mangohud
Required: bash cpulimit coreutils x11-utils
Optional: mangohud mangohud:i386
Required: bash util-linux cpulimit coreutils xprop xwininfo
Optional: MangoHud MangoHud-32bit
Required: bash util-linux cpulimit coreutils xprop xwininfo
Optional: mangohud mangohud.i686
Required: bash util-linux cpulimit coreutils xprop xwininfo
Optional: mangohud mangohud-32bit
Required: app-shells/bash sys-apps/util-linux app-admin/cpulimit sys-apps/coreutils x11-apps/xprop x11-apps/xwininfo
Optional: mangohud (is not packaged)
Dependencies for other distributions will be added soon.
You can use this method if there is no package build script for your distro. Make sure you have installed dependencies as described above before continue.
fluxver='1.8' # set latest version as I update it here every releasemkdir flux && cd flux # create and change build directorywget https://github.com/itz-me-zappex/flux/archive/refs/tags/v${fluxver}.tar.gz # download archive with releasetar -xvf v${fluxver}.tar.gz # extract itsudo install -Dm 755 flux-${fluxver}/flux /usr/local/bin/flux # install daemon to `/usr/local/bin`Make sure you have installed base-devel package before continue.
fluxver='1.8' # set latest version as I update it here every releasemkdir flux && cd flux # create and change build directorywget https://github.com/itz-me-zappex/flux/releases/download/v${fluxver}/PKGBUILD # download PKGBUILDmakepkg -sric # build a package and install itfluxver='1.8' # set latest version as I update it here every releasemkdir flux && cd flux # create and change build directorywget https://github.com/itz-me-zappex/flux/releases/download/v${fluxver}/build-deb.sh # download build scriptchmod +x build-deb.sh # make it executable./build-deb.sh # build a packagesudo dpkg -i flux-v${fluxver}.deb ; sudo apt install -f # install a packageUsage: flux [-c <…>] [-f] [-h] [-H] [-Hl] [-L <…>] [-p] [-q] [-u] [-v] [-V]
Options and values:
-c, --config <…> Specify path to config file
-f, --focused Display info about focused window in usable for config file way
-h, --help Display this help
-H, --hot Apply actions to already unfocused windows before handling events
-l, --lazy Avoid focus and unfocus commands on hot, use only with '--hot'
-L, --log <…> Store output to specified file
-p, --pick Display info about picked window in usable for config file way
-q, --quiet Display errors and warnings only
-u, --usage Same as '--help'
-v, --verbose Detailed output
-V, --version Display release information
Prefixes configuration:
--prefix-error Default: [e]
--prefix-info Default: [i]
--prefix-verbose Default: [v]
--prefix-warning Default: [w]
Logging configuration, use only with '--log':
--log-disable-timestamps Do not store timestamps in log, do not use with '--log-timestamp'
--log-overwrite Clean log file before start
--log-timestamp <…> Set timestamp format, default: %Y-%m-%dT%H:%M:%S%z
Just add command to autostart using your DE settings or WM config. Running daemon as root also possible, but that feature almost useless.
A simple INI is used for configuration. Available keys and description:
| Key | Description |
|---|---|
name |
Name of process, gets from /proc/<PID>/comm, required if neither executable nor command is specified. |
executable |
Path to binary of process, gets by reading /proc/<PID>/exe symlink, required if neither name nor command is specified. |
owner |
User ID of process, gets from /proc/<PID>/status. |
cpu-limit |
CPU limit between 0% and 100%, defaults to -1% which means no CPU limit, % symbol is optional. |
delay |
Delay in seconds before applying CPU/FPS limit. Optional, defaults to 0, supports values with floating point. |
focus |
Command to execute on focus event, command runs via bash and will not be killed on daemon exit, output is hidden to avoid mess in output of daemon. |
unfocus |
Command to execute on unfocus event, command runs via bash and will not be killed on daemon exit, output is hidden to avoid mess in output of daemon. |
command |
Command of process, gets from /proc/<PID>/cmdline, required if neither name nor executable is specified. |
mangohud-config |
Path to MangoHud config, required if you want change FPS limits and requires fps-unfocus. DO NOT USE THE SAME CONFIG FOR MULTIPLE SECTIONS! |
fps-unfocus |
FPS to set on unfocus, required by and requires mangohud-config, cannot be equal to 0 as that means no limit. |
fps-focus |
FPS to set on focus, requires fps-unfocus, defaults to 0 (i.e. no limit). |
- Daemon searches for following configuration files by priority:
$XDG_CONFIG_HOME/flux.ini~/.config/flux.ini/etc/flux.ini
As INI is not standartized, I should mention all supported features here.
- Supported
- Spaces in section names.
- Single and double quoted strings.
- Commented lines and inline comments using
;and/or#symbols. - Сase insensitive name of keys.
- Insensetivity to spaces before and after
=symbol.
- Unsupported
- Regular expressions.
- Inline comment on lines with section name.
- Line continuation using
\symbol. - Anything else what unmentioned above.
Tip: Use --focus or --pick option to obtain info about process in usable for configuration way from focused window or by picking it respectively.
; Example using freezing as that is single player game
[The Witcher 3: Wild Hunt]
name = witcher3.exe
executable = /home/zappex/.local/share/Steam/steamapps/common/Proton 8.0/dist/bin/wine64-preloader
command = Z:\run\media\zappex\WD-BLUE\Games\Steam\steamapps\common\The Witcher 3\bin\x64\witcher3.exe
owner = 1000
cpu-limit = 0%
focus = killall picom
unfocus = picom
; Example using FPS limit as that is online game and I use MangoHud
[Forza Horizon 4]
name = ForzaHorizon4.e
executable = /run/media/zappex/WD-BLUE/Games/Steam/steamapps/common/Proton 9.0 (Beta)/files/bin/wine64-preloader
command = Z:\run\media\zappex\WD-BLUE\Games\Steam\steamapps\common\ForzaHorizon4\ForzaHorizon4.exe
owner = 1000
mangohud-config = /home/zappex/.config/MangoHud/wine-ForzaHorizon4.conf
fps-unfocus = 5 ; FPS to set on unfocus event
fps-focus = 60 ; I have 60 FPS lock, so I want restore it on focus event
focus = killall picom
unfocus = picom
; Example using CPU limit as game does not consume GPU resources if minimized but still uses CPU and requires network connection to download levels and music
[Geometry Dash]
name = GeometryDash.ex
executable = /home/zappex/.local/share/Steam/steamapps/common/Proton 8.0/dist/bin/wine64-preloader
command = Z:\run\media\zappex\WD-BLUE\Games\Steam\steamapps\common\Geometry Dash\GeometryDash.exe
owner = 1000
cpu-limit = 2%
focus = killall picom
unfocus = picom; Example using freezing as that is single player game
[The Witcher 3: Wild Hunt]
name = witcher3.exe
cpu-limit = 0%
; Example using FPS limit as that is online game and I use MangoHud
[Forza Horizon 4]
name = ForzaHorizon4.e
mangohud-config = /home/zappex/.config/MangoHud/wine-ForzaHorizon4.conf
fps-unfocus = 5 ; FPS to set on unfocus event
fps-focus = 60 ; I have 60 FPS lock, so I want restore it on focus event
; Example using CPU limit as game does not consume GPU resources if minimized but still uses CPU and requires network connection to download levels and music
[Geometry Dash]
name = GeometryDash.ex
cpu-limit = 2%Flux does not support environment variables, but passes them to commands in focus and unfocus keys.
| Variable | Description |
|---|---|
FLUX_WINDOW_ID |
ID of focused window |
FLUX_PROCESS_PID |
Process PID of focused window |
FLUX_PROCESS_NAME |
Process name of focused window |
FLUX_PROCESS_EXECUTABLE |
Path to process binary |
FLUX_PROCESS_OWNER |
UID of process |
FLUX_PROCESS_COMMAND |
Command of process |
Daemon passes absolutely same values for both focus and unfocus commands.
- All you need is install
xcliptool and bind this command:$ flux --focus | xclip -selection clipboard. Now you can easily grab templates from windows to use them in config by pasting content usingCtrl+v.
- Create shortcut for
$ killall flux ; flux --hot --lazycommand which restarts daemon and use it when you done config file editing.
- Geeks only, casual users should not care about that. To do that, run daemon using command like
$ chrt --batch 0 flux --hot --lazy.SCHED_BATCHscheduling policy is designed to improve performance of non-interactive tasks like daemons, timers, scripts etc..
- FPS limits recommended for online and multiplayer games and if you do not mind to use MangoHud, this method reduces resource consumption when game unfocused/minimized.
- CPU limits greater than zero recommended for online and multiplayer games in case you do not use MangoHud, but you should be ready to stuttery audio as
cpulimittool interrupts process withSIGSTOPandSIGCONTsignals. - CPU limit equal to zero recommended for single player games or online games in offline mode, this method freezes game completely to make it just hang in RAM without using any CPU or GPU resources.
- Daemon reads X11 events related to window focus, then it gets PID of process using window ID via
xproptool and uses it to collect info about process (process name, its executable path, command which is used to run it and effective UID) to compare it with identifiers in config, if it finds window which matches with identifier(s) specified in specific section in config, it can run command fromfocuskey, in case you switch to another window - apply FPS or CPU limit and run command fromunfocuskey (if all of those has been specified in config of course). If window does not match with any section in config, nothing happens. To reduce CPU usage and speed up daemon I implemented a caching algorithm which stores info about windows and processes into associative arrays, that allows to collect info about process and window once and then use cache to get this info immediately, if window with the same ID or if new window with the same PID appears (in this case it runsxpropto get window ID and searches for cached info about this process), daemon uses cache to get info. Do not worry, daemon forgets info about window and process immediately if window disappears (i.e. becomes closed, not minimized), so memory leak should not occur.
- Long story short, impact on neither performance nor battery life should be noticeable. It uses event-based algorithm to obtain info about windows and processes, when you switching between windows daemon consumes a bit CPU time, but it just chills out when you playing game or working in single window.
- Yes, read above. Neither I nor daemon has access to your data.
- You can read entire code. If you are uncomfortable, feel free to avoid using it.
- Daemon compatible with all X11 window managers and desktop environments and does not depend on neither GPU nor driver version as it relies on X11 event system.
- Just put config file to
/etc/flux.iniand make it read-only, also do something like that with scripts you interacting with from config file.
- Nowadays, anti-cheats are pure garbage, developed by freaks without balls, and you can get banned even for a wrong click. But that is should not be bannable except you are farmer and using sandboxing. Do not write me if you got a ban in game.
- Main task is to reduce CPU usage of games that have been minimized. Almost every engine fails to recognize that game is unfocused and continues to consume a lot of CPU and GPU resources, what can make system slow for other tasks like browsing stuff, transcoding video etc. or even unresponsive at all. Imagine users with weak laptop who upgraded their RAM to maximum and suffer from a weak processor, now they can simply play a game and then minimize it if needed without carrying about CPU usage or battery level as process will just hang in RAM. To be honest, inspiried by feature from NVIDIA driver for Windows, where user can set FPS limit for minimized software, this tool is not exactly the same, but better than nothing.
- Nothing is perfect in this world. Almost all bugs I encountered during development have been fixed or will be fixed soon. If you find a bug, open an issue. Known issues that cannot be fixed are:
- Inability to interact with "glxgears" and "vkcube" windows, as they do not report their PIDs.
- Freezing online games (setting
cpu-limitto0%) causes disconnects from matches, so use less aggressive CPU limit to allow game to send/receive packets. - Stuttery audio in game if CPU limit is very aggressive, as
cpulimittool interrupts process, that should be expected.
- Long story short, try removing at least one line of code (that does not affect output, of course) and see what happens. That sounds easy - just apply a CPU limit to a window when unfocused and remove it when focused, but that is a bit more complicated. Just check how much logic is used for that "easy" task. Also I used built-in stuff in bash like shell parameter expansions instead of
sed, loops for reading text line-by-line with regexp inifstatements instead ofgrepetc. to make code faster, calling external binaries consumes much more time and CPU resources than built-in options.
Gamescope which allows limit FPS on unfocus exists, Wayland becomes more popular. Are you not late by any chance?
- Well, not everyone is ready for switch to Wayland, there are a lot of reasons exists. Gamescope does not work well on my desktop with NVIDIA GPU and laptop with Inter APU, and I can bet it does not work well for others either. Also, there are a lot of old NVIDIA GPUs that do not support Wayland at all because of old drivers, what makes Gamescope completely useless for owners of these GPUs because it depends on Wayland.
- That is impossible, there is no any unified way to read window focus events and extract PIDs from windows on Wayland.
- That is (scripting) language I know pretty good, despite a fact that Bash as all interpretators works slower than compilable languages, it still fits my needs almost perfectly.