nixos/modules/system/default.nix

inputs:
{
	options.nixos.system = let inherit (inputs.lib) mkOption types; in
	{
		hostname = mkOption { type = types.nonEmptyStr; };
    march = mkOption { type = types.nullOr types.nonEmptyStr; };
	};
	config = let inherit (inputs.lib) mkMerge mkIf; inherit (inputs.localLib) mkConditional stripeTabs; in mkMerge
	[
    # generic
    {
      nix =
      {
        settings =
        {
          system-features = [ "big-parallel" "nixos-test" "benchmark" ];
          experimental-features = [ "nix-command" "flakes" ];
          keep-outputs = true;
          keep-failed = true;
          auto-optimise-store = true;
        };
        daemonIOSchedClass = "idle";
        daemonCPUSchedPolicy = "idle";
        registry =
        {
          nixpkgs.flake = inputs.topInputs.nixpkgs;
          nixos-config.flake = inputs.topInputs.self;
        };
      };
      services =
      {
        udev.extraRules = stripeTabs
        ''
          ACTION=="add|change", KERNEL=="[sv]d[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="bfq"
          ACTION=="add|change", KERNEL=="nvme[0-9]n[0-9]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="bfq"
        '';
        dbus.implementation = "broker";
      };
      networking.networkmanager.enable = true;
      programs = { dconf.enable = true; nix-ld.enable = true; };
      nixpkgs.config.allowUnfree = true;
      time.timeZone = "Asia/Shanghai";
      system =
      {
        stateVersion = "22.11";
        configurationRevision = inputs.topInputs.self.rev or "dirty";
      };
      boot =
      {
        kernel.sysctl =
        {
          "net.core.rmem_max" = 67108864;
          "net.core.wmem_max" = 67108864;
          "net.ipv4.tcp_rmem" = "4096 87380 67108864";
          "net.ipv4.tcp_wmem" = "4096 65536 67108864";
          "net.ipv4.tcp_mtu_probing" = true;
          "net.ipv4.tcp_tw_reuse" = true;
          "vm.swappiness" = 10;
          "net.ipv4.tcp_max_syn_backlog" = 8388608;
          "net.core.netdev_max_backlog" = 8388608;
          "net.core.somaxconn" = 8388608;
          "vm.oom_kill_allocating_task" = true;
          "vm.oom_dump_tasks" = false;
          "vm.overcommit_memory" = 1;
          "dev.i915.perf_stream_paranoid" = false;
        };
        supportedFilesystems = [ "ntfs" ];
        consoleLogLevel = 7;
      };
      hardware.enableAllFirmware = true;
      systemd =
      {
        extraConfig = stripeTabs
        "
          DefaultTimeoutStopSec=10s
          DefaultLimitNOFILE=1048576:1048576
        ";
        user.extraConfig = "DefaultTimeoutStopSec=10s";
        services =
        {
          nix-daemon =
          {
            serviceConfig = { CacheDirectory = "nix"; Slice = "-.slice"; Nice = "19"; };
            environment = { TMPDIR = "/var/cache/nix"; };
          };
          systemd-tmpfiles-setup = { environment = { SYSTEMD_TMPFILES_FORCE_SUBVOL = "0"; }; };
        };
        timers.systemd-tmpfiles-clean.enable = false;
      };
    }
    # hostname
    { networking.hostName = inputs.config.nixos.system.hostname; }
    # march
    (
      mkConditional (inputs.config.nixos.system.march != null)
        {
          nixpkgs =
          {
            hostPlatform = { system = "x86_64-linux"; gcc =
              { arch = inputs.config.nixos.system.march; tune = inputs.config.nixos.system.march; }; };
            config.qchem-config.optArch = inputs.config.nixos.system.march;
          };
          nix.settings.system-features = [ "gccarch-${inputs.config.nixos.system.march}" ];
          boot.kernelPatches =
          [{
            name = "native kernel";
            patch = null;
            extraStructuredConfig =
            {
              GENERIC_CPU = inputs.lib.kernel.no;
              "M${inputs.lib.strings.toUpper inputs.config.nixos.system.march}" = inputs.lib.kernel.yes;
            };
          }];
        }
        { nixpkgs.hostPlatform = inputs.lib.mkDefault "x86_64-linux"; }
    )
  ];
}