machine_setup/nix/configuration/hosts/odo/optimized_build.nix

{
  config,
  lib,
  pkgs,
  ...
}:
{
  imports = [ ];

  nix.settings.system-features = lib.mkForce [
    "gccarch-znver4"
    "gccarch-skylake"
    # "gccarch-alderlake" missing WAITPKG
    "gccarch-x86-64-v3"
    "gccarch-x86-64-v4"
    "benchmark"
    "big-parallel"
    "kvm"
    "nixos-test"
  ];

  # nixpkgs.hostPlatform = {
  #   gcc.arch = "znver4";
  #   gcc.tune = "znver4";
  #   system = "x86_64-linux";
  # };

  nixpkgs.overlays = [
    (
      self: super:
      let
        optimizeWithFlags =
          pkg: flags:
          pkg.overrideAttrs (old: {
            NIX_CFLAGS_COMPILE = [ (old.NIX_CFLAGS_COMPILE or "") ] ++ flags;
          });
      in
      {
        # linux
        # linux_6_11
        # linux_zen
        linux_znver4 = optimizeWithFlags super.linux_6_11 [
          "-march=znver4"
          "-mtune=znver4"
        ];
      }
    )
    # (
    #   self: super:
    #   let
    #     optimizeWithFlags =
    #       pkg: flags:
    #       pkg.overrideAttrs (old: {
    #         NIX_CFLAGS_COMPILE = [ (old.NIX_CFLAGS_COMPILE or "") ] ++ flags;
    #       });
    #     addConfig =
    #       additionalConfig: pkg:
    #       pkg.override (oldconfig: {
    #         structuredExtraConfig = pkg.structuredExtraConfig // additionalConfig;
    #       });
    #   in
    #   {
    #     linux_znver4 =
    #       addConfig
    #         {
    #           # CPUFreq governor Performance
    #           CPU_FREQ_DEFAULT_GOV_PERFORMANCE = lib.mkOverride 60 lib.kernel.yes;
    #           CPU_FREQ_DEFAULT_GOV_SCHEDUTIL = lib.mkOverride 60 lib.kernel.no;

    #           # Full preemption
    #           PREEMPT = lib.mkOverride 60 lib.kernel.yes;
    #           PREEMPT_VOLUNTARY = lib.mkOverride 60 lib.kernel.no;

    #           # Google's BBRv3 TCP congestion Control
    #           TCP_CONG_BBR = lib.kernel.yes;
    #           DEFAULT_BBR = lib.kernel.yes;

    #           # Preemptive Full Tickless Kernel at 250Hz
    #           HZ = lib.kernel.freeform "250";
    #           HZ_250 = lib.kernel.yes;
    #           HZ_1000 = lib.kernel.no;
    #         }
    #         (
    #           optimizeWithFlags super.linux_6_11 [
    #             "-march=znver4"
    #             "-mtune=znver4"
    #           ]
    #         );
    #   }
    # )
  ];

  boot.kernelPackages = lib.mkIf (!config.me.buildingIso) (pkgs.linuxPackagesFor pkgs.linux_znver4);
}