Ikey Doherty e90bd98d64 Enforce strict compiler warnings
This exposed a bunch of issues that needed dealing with to ensure the
code is clean and sane. Notably the dlopen/dlsym routine has been altered
to closer match the LSI approach of safe symbol binding, by not attempting
to directly cast the result of a dlsym operation. Instead, if we succeed
in getting the dlsym() pointer, we memcpy this to the target and ensure
we have the correct constraints.

Note that in sanitizing the log helpers, I opted to remove the varargs
ability from FATAL_ERRNO given this is used exactly like perror() and
there are no examples currently using varargs with this in the tree.
This allowed me to keep the log helpers as macros and not have to implement
wrapper functions.

Signed-off-by: Ikey Doherty <ikey@solus-project.com>
2018-03-05 17:32:26 +00:00
2018-03-05 17:32:26 +00:00
2018-03-05 17:32:26 +00:00
2018-03-05 17:32:26 +00:00
2018-03-05 17:32:01 +00:00
2018-03-05 17:32:01 +00:00
2018-03-05 17:32:01 +00:00
2018-03-05 17:32:01 +00:00
2018-03-05 17:32:26 +00:00

GameMode

A preliminary implementation of a daemon/lib combo to allow games to request a performance mode from the host OS on Linux. It was designed primarily as a stop-gap solution to problems with the Intel and AMD CPU powersave or ondemand governors, but is intended to be expanded beyond just CPU power states as needed.

Currently using sd-bus on the user bus internally for messaging


Components

Host

gamemoded

Runs in the background, waits for requests, refcounts and also checks caller PID lifetime.

Accepts -d (daemonize) and -l (log to syslog)

libgamemode

Dynamic library to dispatch requests to the daemon

Note: Behaviour of gamemoded may change, so libgamemode should never be linked with directly.

cpugovctl

Small program used to to control the cpu governor.

Accepts get (gets current governor) and set <GOVERNOR> (sets the current governor).

Clients

libgamemodeauto

Simple dynamic library that automatically requests game mode when loaded. Minimal dependencies.

Useful to LD_PRELOAD into any game as needed.

gamemode_client.h

Very small header only lib that lets a game request game mode and handle errors. Minimal dependencies.

Can also be included with GAMEMODE_AUTO defined to behave automatically.


Build and install

Daemon and host library

Dependencies

  • meson
  • systemd
# Ubuntu
apt install meson libsystemd-dev
# Arch
pacman -S meson systemd
git clone <git repo>
cd gamemode
meson --prefix=/usr build
cd build
ninja
sudo ninja install

Using with any game or program

After installing libgamemodeauto.so simple preload it into the program. Examples:

LD_PRELOAD=/usr/\$LIB/libgamemodeauto.so ./game

Or steam launch options

LD_PRELOAD=/usr/\$LIB/libgamemodeauto.so %command%

Building into a game or program

You may want to build in functionality directly into an app, this stops the need for users to have to manually set anything up.

gamemode_client.h and libgamemodeauto are safe to use regardless of whether libgamemode and gamemoded are installed on the system. They also do not require systemd.

Using directly

#include "gamemode_client.h"

	if( gamemode_request_start() < 0 )
		fprintf( stderr, "gamemode request failed: %s\n", gamemode_error_string() );

	/* run game... */

	gamemode_request_end(); // Not required, gamemoded will clean up after game exists anyway

Using automatically

Option 1: Include in code

#define GAMEMODE_AUTO
#include "gamemode_client.h"

Add -lgamemodeauto to linker arguments and distribute libgamemodeauto.so with the game

Option 3: Distribute and script

Distribute libgamemodeauto.so with the game and add to LD_PRELOAD in a launch script


Pull Requests

Pull requests must match with the coding style found in the .clang-format file

clang-format -i $(find . -name '*.[ch]')

TODO

  • Use polkit for cpugovctl (currently simply using chmod +4555)
  • Implement some kind of user confuguration to allow for whitelists, extra behaviour, etc.
Description
Optimise Linux system performance on demand
Readme 1.4 MiB
Languages
C 90%
Meson 5.5%
Roff 2.9%
Shell 1.6%