alqueva/hosts/micronix/system.nix

# Edit this configuration file to define what should be installed on
# your system.  Help is available in the configuration.nix(5) man page
# and in the NixOS manual (accessible by running ‘nixos-help’).
{pkgs, ...}: {
  boot.initrd.systemd = {
    enable = true;
    tpm2 = {enable = true;};
    dbus = {enable = true;};
  };

  boot.kernelPackages = pkgs.linuxPackages_latest;

  boot.kernelParams = [
    "default_hugepagesz=1G"
    "hugepagesz=1G"
  ];

  boot.kernel.sysctl = {
    "vm.nr_hugepages" = 512;
    "vm.swappiness" = 200;
    "net.core.netdev_max_backlog" = 32768;
    "net.core.somaxconn" = 16384;
    "net.core.rmem_default" = 1048576;
    "net.core.rmem_max" = 16777216;
    "net.core.wmem_default" = 1048576;
    "net.core.wmem_max" = 16777216;
    "net.core.optmem_max" = 65536;
    "net.ipv4.tcp_rmem" = "4096 1048576 2097152";
    "net.ipv4.tcp_wmem" = "4096 65536 16777216";
    "net.ipv4.udp_rmem_min" = 8192;
    "net.ipv4.udp_wmem_min" = 8192;
    "net.ipv4.tcp_fastopen" = 3;
    "net.core.default_qdisc" = "cake";
    "net.ipv4.tcp_congestion_control" = "bbr";
    "vm.dirty_ratio" = 20;
    "vm.dirty_background_ratio" = 10;
    "vm.vfs_cache_pressure" = 25;
    "vm.hugetlb_optimize_vmemmap" = 1;
  };

  services.scx = {
    enable = true;
    scheduler = "scx_lavd";
    extraArgs = ["--performance"];
  };

  boot.runSize = "100%";
  boot.devSize = "100%";
  boot.devShmSize = "100%";
  boot.tmp.useTmpfs = true;
  boot.tmp.tmpfsSize = "100%";
  boot.tmp.cleanOnBoot = true;

  fileSystems."/" = {
    fsType = "btrfs";
    options = ["compress=zstd:6" "discard" "flushoncommit" "subvol=@"];
  };

  services.btrfs.autoScrub = {
    fileSystems = ["/"]; # Assuming root is formatted with Btrfs.
    interval = "daily";
    enable = true;
  };

  zramSwap = {
    enable = true;
    priority = 100;
    memoryPercent = 100;
  };

  nix.gc = {
    automatic = true;
    options = "-d";
  };

  nix.optimise.automatic = true;

  nix.settings = {
    experimental-features = "cgroups dynamic-derivations flakes nix-command recursive-nix";
    auto-optimise-store = true;
    http-connections = 0;
    download-buffer-size = 671088640;
    max-jobs = "auto";
    sync-before-registering = true;
    use-cgroups = true;
  };

  boot.initrd.kernelModules = ["amdgpu"];

  # Processor settings for AMD
  hardware.cpu.amd = {
    sev.enable = true;
    updateMicrocode = true;
  };

  # Bootloader.
  boot.loader.systemd-boot = {
    enable = true;
    edk2-uefi-shell = {enable = true;};
    memtest86 = {enable = true;};
    configurationLimit = 3;
  };

  boot.plymouth = {
    enable = true;
  };

  networking.tempAddresses = "default";

  # Load AMD GPU drivers early
  hardware.amdgpu.initrd = {
    enable = true;
  };

  hardware.amdgpu.opencl = {
    enable = true;
  };

  # Graphics
  hardware.graphics = {
    enable = true;
    enable32Bit = true;
  };

  # Enable the X11 windowing system.
  services.xserver.enable = true;
  services.xserver.videoDrivers = ["amdgpu"];
  services.xserver.updateDbusEnvironment = true;
  services.xserver.enableTearFree = true;

  qt = {
    platformTheme = "gnome";
  };

  # TLP
  services.power-profiles-daemon.enable = false; # We disable this because it sucks
  services.tlp.enable = true;
  services.tlp.settings = {
    CPU_DRIVER_OPMODE_ON_AC = "active";
    CPU_DRIVER_OPMODE_ON_BAT = "active";
    CPU_SCALING_GOVERNOR_ON_AC = "performance";
    CPU_SCALING_GOVERNOR_ON_BAT = "schedutil";
    CPU_BOOST_ON_AC = 1;
    CPU_BOOST_ON_BAT = 0;
    PLATFORM_PROFILE_ON_AC = "performance";
    PLATFORM_PROFILE_ON_BAT = "low-power";
    DISK_IOSCHED = "kyber";
    RADEON_DPM_PERF_LEVEL_ON_AC = "high";
    WIFI_PWR_ON_AC = "off";
    WIFI_PWR_ON_BAT = "off";
  };

  # Enable sound with pipewire.
  hardware.pulseaudio.enable = false;
  security.rtkit.enable = true;
  services.pipewire = {
    enable = true;
    alsa.enable = true;
    alsa.support32Bit = true;
    pulse.enable = true;
    jack.enable = true;
  };

  services.displayManager.sddm.enable = true;
  services.displayManager.sddm.wayland.enable = true;

  programs.dconf.enable = true;

  xdg.portal.enable = true;
  xdg.portal.xdgOpenUsePortal = true;

  services.dbus = {
    implementation = "broker";
  };

  # SECURITY
  security = {
    tpm2 = {
      enable = true;
    }; # Having TPM2 is nice.
    polkit = {
      enable = true;
    };
    protectKernelImage = true;
    forcePageTableIsolation = true;
  };

  systemd.tpm2.enable = true;
}