* If power management is enabled, set the governor to ‘ondemand’ by

default.  See
  
    http://www.codon.org.uk/~mjg59/power/good_practices.html
    
  for the reasoning.  (Basically, the ‘performance’ and ‘powersave’
  governors don't actually provide extra performance or power savings
  in most cases.)

  It used to be that desktop environments like KDE were able to set
  the governor through HAL (e.g. KDE could be configured to switch to
  the powersave governor when the user unplugs his laptop).  However,
  this is no longer the case with upower — it is now expected that
  everybody uses the ondemand governor.  See

    http://old.nabble.com/-PATCH--powerdevil-remove-cpufreq.patch-td27815354.html

* Rename ‘cpuFreqGovernor’ to ‘powerManagement.cpuFreqGovernor’.

* Include cpufreq-utils in the system path if a governor is set, since
  we depend on it anyway.

svn path=/nixos/trunk/; revision=30991
This commit is contained in:
Eelco Dolstra 2011-12-20 22:44:58 +00:00
parent 2ff7b1284a
commit cf36b3db80
2 changed files with 13 additions and 5 deletions

View File

@ -91,6 +91,8 @@ in
"p4_clockmod"
];
powerManagement.cpuFreqGovernor = "ondemand";
};
}

View File

@ -6,7 +6,8 @@ with pkgs.lib;
###### interface
options = {
cpuFreqGovernor = mkOption {
powerManagement.cpuFreqGovernor = mkOption {
default = "";
example = "ondemand";
description = ''
@ -15,13 +16,17 @@ with pkgs.lib;
"userspace".
'';
};
};
###### implementation
config = mkIf (config.cpuFreqGovernor != "") ({
jobs.cpuFreq =
config = mkIf (config.powerManagement.cpuFreqGovernor != "") {
environment.systemPackages = [ pkgs.cpufrequtils ];
jobs.cpufreq =
{ description = "Initialize CPU frequency governor";
startOn = "started udev";
@ -30,10 +35,11 @@ with pkgs.lib;
script = ''
for i in $(seq 0 $(($(nproc) - 1))); do
${pkgs.cpufrequtils}/bin/cpufreq-set -g ${config.cpuFreqGovernor} -c $i
${pkgs.cpufrequtils}/bin/cpufreq-set -g ${config.powerManagement.cpuFreqGovernor} -c $i
done
'';
};
});
};
}