systemd-bootchart.nix WIP

systemd-bootchart.nix

{ config, lib, pkgs, ... }:

with lib;

let

  cfg = config.services.systemd-bootchart;

  systemd-bootchart = with pkgs; stdenv.mkDerivation rec {
    version = "230";
    name = "systemd-bootchart-v${version}";
    src = fetchFromGitHub {
      owner = "systemd";
      repo = "systemd-bootchart";
      rev = "v${version}";
      sha256 = "1dbscx7hsvn6a5rbjfmpskwnp0n2hpwdb8n85gssnlmxas7cw72f";
    };

    postPatch = ''
      substituteInPlace man/custom-man.xsl --replace \
        http://docbook.sourceforge.net/release/xsl/current/manpages \
        ${docbook_xsl}/xml/xsl/docbook/manpages

      substituteInPlace man/standard-options.xml --replace \
        http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd \
        ${docbook_xml_dtd_45}/xml/dtd/docbook/docbookx.dtd

      substituteInPlace man/standard-conf.xml --replace \
        http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd \
        ${docbook_xml_dtd_45}/xml/dtd/docbook/docbookx.dtd

      substituteInPlace man/systemd-bootchart.xml --replace \
        http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd \
        ${docbook_xml_dtd_42}/xml/dtd/docbook/docbookx.dtd

      substituteInPlace man/bootchart.conf.xml --replace \
        http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd \
        ${docbook_xml_dtd_42}/xml/dtd/docbook/docbookx.dtd
    '';

    preConfigure = "./autogen.sh";
    configureFlags = [ "--with-rootprefix=$(out)" ];

    buildInputs = [
      autoconf automake pkgconfig libtool intltool systemd libxslt.bin
      docbook_xsl docbook_xml_dtd_45 docbook_xml_dtd_42
    ];

    postInstall = ''
      rm -f $out/etc/systemd/bootchart.conf
      ln -s /etc/systemd/bootchart.conf $out/etc/systemd/bootchart.conf
    '';

    meta = with stdenv.lib; {
      homepage = https://github.com/systemd/systemd-bootchart;
      description = "Boot performance graphing tool";
      license = with licenses; [ gpl2Plus lgpl21Plus ];
      platforms = platforms.linux;
    };
  };

in
{
  options = {
    services.systemd-bootchart = {
      enable = mkOption {
        default = false;
        description = ''
          Enable the boot performance graphing tool.
        '';
      };

      daemon = mkOption {
        default = true;
        description = ''
          Enable the boot performance graphing tool daemon.
          Disables the default kernel command line <literal>init=</literal> option.
          Note: Kernel <literal>init=</literal> is currently unimplemented.
        '';
      };

      samples = mkOption {
        default = "500";
        description = ''
          Configure the amount of samples to record in total before bootchart exits.
          Each sample will record at intervals defined by <literal>frequency=</literal>.
        '';
      };

      frequency = mkOption {
        default = "25";
        description = ''
          Configure the sample log frequency.
          This can be a fractional number, but must be larger than <literal>0.0</literal>.
          Most systems can cope with values under <literal>25–50</literal> without impacting boot time severely.
        '';
      };

      relative = mkOption {
        default = "no";
        description = ''
          Configures whether the left axis of the output graph equals <literal>time=0.0</literal> (<literal>CLOCK_MONOTONIC</literal> start).
          This is useful for using bootchart at post-boot time to profile an already booted system, otherwise the graph would become extremely large.
          If set to yes, the horizontal axis starts at the first recorded sample instead of <literal>time=0.0</literal>. 
        '';
      };

      filter = mkOption {
        default = "yes";
        description = ''
          Configures whether the resulting graph should omit tasks that did not contribute significantly to the boot.
          Processes that are too short-lived (only seen in one sample) or that do not consume any significant CPU time (less than <literal>0.001sec</literal>) will not be displayed in the output graph.
        '';
      };

      output = mkOption {
        default = "/run/log";
        description = ''
          Configures the output directory for writing the graphs.
          By default, bootchart writes the graphs to <literal>/run/log</literal>.
        '';
      };

      init = mkOption {
        default = "${systemd}/lib/systemd/systemd";
        description = ''
          Configures bootchart to run a non-standard binary instead of <literal>/usr/lib/systemd/systemd</literal>.
          This option is only relevant if bootchart was invoked from the kernel command line with <literal>init=/usr/lib/systemd/systemd-bootchart</literal>.
          Note: Kernel <literal>init=</literal> is currently unimplemented.
        '';
      };

      plotMemoryUsage = mkOption {
        default = "no";
        description = ''
          If set to yes, enables logging and graphing of processes' PSS memory consumption.
        '';
      };

      plotEntropyGraph = mkOption {
        default = "no";
        description = ''
          If set to yes, enables logging and graphing of the kernel random entropy pool size.
        '';
      };

      scaleX = mkOption {
        default = "100";
        description = ''
          Horizontal scaling factor for all variable graph components.
        '';
      };

      scaleY = mkOption {
        default = "20";
        description = ''
          Vertical scaling factor for all variable graph components.
        '';
      };

      controlGroup = mkOption {
        default = "no";
        description = ''
          Display process control group.
        '';
      };

      perCPU = mkOption {
        default = "no";
        description = ''
          Display per CPU.
        '';
      };
    };
  };

  config = mkIf cfg.enable {
    environment.etc."systemd/bootchart.conf".text = ''
      #  This file is part of systemd.
      #
      #  systemd is free software; you can redistribute it and/or modify it
      #  under the terms of the GNU Lesser General Public License as published by
      #  the Free Software Foundation; either version 2.1 of the License, or
      #  (at your option) any later version.
      #
      # Entries in this file show the compile time defaults.
      # You can change settings by editing this file.
      # Defaults can be restored by simply deleting this file.
      #
      # See bootchart.conf(5) for details.

      [Bootchart]
      Samples=${cfg.samples}
      Frequency=${cfg.frequency}
      Relative=${cfg.relative}
      Filter=${cfg.filter}
      Output=${cfg.output}
      Init=${cfg.init}
      PlotMemoryUsage=${cfg.plotMemoryUsage}
      PlotEntropyGraph=${cfg.plotEntropyGraph}
      ScaleX=${cfg.scaleX}
      ScaleY=${cfg.scaleY}
      ControlGroup=${cfg.controlGroup}
      PerCPU=${cfg.perCPU}

    '';

    #TODO: Implement real init=${systemd-bootchart}/lib/systemd/systemd-bootchart instead of a daemon.
    #journalctl -b -F BOOTCHART --full
    systemd.services = mkIf cfg.daemon {
      systemd-bootchart = {
        description = "Boot Process Profiler";
        documentation = "man:systemd-bootchart.service(1) man:bootchart.conf(5)";
        defaultDependencies = "no";
        wantedBy = [ "sysinit.target" ];

        serviceConfig.ExecStart = "${systemd-bootchart}/lib/systemd/systemd-bootchart -r";
      };
    };

  environment.systemPackages = [ systemd-bootchart ];
  };
}