1 files changed, 90 insertions, 0 deletions
diff --git a/nixpkgs/nixos/modules/tasks/cpu-freq.nix b/nixpkgs/nixos/modules/tasks/cpu-freq.nix
new file mode 100644
index 00000000000..513382936e4
--- /dev/null
+++ b/nixpkgs/nixos/modules/tasks/cpu-freq.nix
@@ -0,0 +1,90 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cpupower = config.boot.kernelPackages.cpupower;
+  cfg = config.powerManagement;
+in
+
+{
+  ###### interface
+
+  options.powerManagement = {
+
+    # TODO: This should be aliased to powerManagement.cpufreq.governor.
+    # https://github.com/NixOS/nixpkgs/pull/53041#commitcomment-31825338
+    cpuFreqGovernor = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "ondemand";
+      description = ''
+        Configure the governor used to regulate the frequence of the
+        available CPUs. By default, the kernel configures the
+        performance governor, although this may be overwritten in your
+        hardware-configuration.nix file.
+
+        Often used values: "ondemand", "powersave", "performance"
+      '';
+    };
+
+    cpufreq = {
+
+      max = mkOption {
+        type = types.nullOr types.ints.unsigned;
+        default = null;
+        example = 2200000;
+        description = ''
+          The maximum frequency the CPU will use.  Defaults to the maximum possible.
+        '';
+      };
+
+      min = mkOption {
+        type = types.nullOr types.ints.unsigned;
+        default = null;
+        example = 800000;
+        description = ''
+          The minimum frequency the CPU will use.
+        '';
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config =
+    let
+      governorEnable = cfg.cpuFreqGovernor != null;
+      maxEnable = cfg.cpufreq.max != null;
+      minEnable = cfg.cpufreq.min != null;
+      enable =
+        !config.boot.isContainer &&
+        (governorEnable || maxEnable || minEnable);
+    in
+    mkIf enable {
+
+      boot.kernelModules = optional governorEnable "cpufreq_${cfg.cpuFreqGovernor}";
+
+      environment.systemPackages = [ cpupower ];
+
+      systemd.services.cpufreq = {
+        description = "CPU Frequency Setup";
+        after = [ "systemd-modules-load.service" ];
+        wantedBy = [ "multi-user.target" ];
+        path = [ cpupower pkgs.kmod ];
+        unitConfig.ConditionVirtualization = false;
+        serviceConfig = {
+          Type = "oneshot";
+          RemainAfterExit = "yes";
+          ExecStart = "${cpupower}/bin/cpupower frequency-set " +
+            optionalString governorEnable "--governor ${cfg.cpuFreqGovernor} " +
+            optionalString maxEnable "--max ${toString cfg.cpufreq.max} " +
+            optionalString minEnable "--min ${toString cfg.cpufreq.min} ";
+          SuccessExitStatus = "0 237";
+        };
+      };
+
+  };
+}