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  This file is part of systemd.

  Copyright 2012 Intel Corporation

  Authors:
    Auke Kok <auke-jan.h.kok@intel.com>
    William Giokas <1007380@gmail.com>

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<refentry id="systemd-bootchart" conditional='ENABLE_BOOTCHART'
          xmlns:xi="http://www.w3.org/2001/XInclude">

        <refentryinfo>
                <title>systemd-bootchart</title>
                <productname>systemd</productname>

                <authorgroup>
                        <author>
                                <contrib>Developer</contrib>
                                <firstname>Auke</firstname>
                                <surname>Kok</surname>
                                <email>auke-jan.h.kok@intel.com</email>
                        </author>
                </authorgroup>
        </refentryinfo>

        <refmeta>
                <refentrytitle>systemd-bootchart</refentrytitle>
                <manvolnum>1</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>systemd-bootchart</refname>
                <refpurpose>Boot performance graphing tool</refpurpose>
        </refnamediv>

        <refsect1>
                <title>Description</title>
                <para>
                        <command>systemd-bootchart</command> is a
                        tool, usually run at system startup, that
                        collects the CPU load, disk load, memory
                        usage, as well as per-process information from
                        a running system. Collected results are output
                        as an SVG graph. Normally, systemd-bootchart
                        is invoked by the kernel by passing
                        <option>init=<filename>/usr/lib/systemd/systemd-bootchart</filename></option>
                        on the kernel commandline. systemd-bootchart will then
                        fork the real init off to resume normal system
                        startup, while monitoring and logging startup
                        information in the background.
                </para>
                <para>
                        After collecting a certain amount of data
                        (usually 15-30 seconds, default 20 s) the
                        logging stops and a graph is generated from
                        the logged information. This graph contains
                        vital clues as to which resources are being used,
                        in which order, and where possible problems
                        exist in the startup sequence of the system.
                        It is essentially a more detailed version of
                        the <command>systemd-analyze plot</command>
                        function.
                </para>
                <para>
                        Of course, bootchart can also be used at any
                        moment in time to collect and graph some data
                        for an amount of time. It is
                        recommended to use the <option>--rel</option>
                        switch in this case.
                </para>
                <para>
                        Bootchart does not require root privileges,
                        and will happily run as a normal user.
                </para>
                <para>
                        Bootchart graphs are by default written
                        time-stamped in <filename>/run/log</filename>
                        and saved to the journal with
                        <varname>MESSAGE_ID=9f26aa562cf440c2b16c773d0479b518</varname>.
                        Journal field <varname>BOOTCHART=</varname> contains
                        the bootchart in SVG format.
                </para>

        </refsect1>

        <refsect1>
                <title>Invocation</title>

                <para><command>systemd-bootchart</command> can be invoked in several different ways:</para>

                <variablelist>

                        <varlistentry>
                                <term><emphasis>Kernel invocation</emphasis></term>
                                <listitem><para>The kernel can invoke
                                <command>systemd-bootchart</command>
                                instead of the init process. In turn,
                                <command>systemd-bootchart</command>
                                will invoke <command>/sbin/init</command>.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><emphasis>Started as a standalone program</emphasis></term>
                                <listitem><para>One can execute
                                <command>systemd-bootchart</command>
                                as normal application from the
                                commandline. In this mode it is highly
                                recommended to pass the
                                <option>-r</option> flag in order to
                                not graph the time elapsed since boot
                                and before systemd-bootchart was
                                started, as it may result in extremely
                                large graphs. The time elapsed since boot
                                might also include any time that the system
                                was suspended.</para></listitem>
                        </varlistentry>
                </variablelist>
        </refsect1>

        <refsect1>
                <title>Options</title>

                <para>These options can also be set in the
                <filename>/etc/systemd/bootchart.conf</filename>
                file. See
                <citerefentry project='man-pages'><refentrytitle>bootchart.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
                </para>

                <variablelist>
                        <xi:include href="standard-options.xml" xpointer="help" />

                        <varlistentry>
                                <term><option>-n</option></term>
                                <term><option>--sample <replaceable>N</replaceable></option></term>
                                <listitem><para>Specify the number of
                                samples, <replaceable>N</replaceable>,
                                to record. Samples will be recorded at
                                intervals defined with <option>--freq</option>.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-f</option></term>
                                <term><option>--freq <replaceable>f</replaceable></option></term>
                                <listitem><para>Specify the sample log
                                frequency, a positive real <replaceable>f</replaceable>, in Hz.
                                Most systems can cope with values up to 25-50 without
                                creating too much overhead.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-r</option></term>
                                <term><option>--rel</option></term>
                                <listitem><para>Use relative times instead of absolute
                                times. This is useful for using bootchart at post-boot
                                time to profile an already booted system. Without this
                                option the graph would become extremely large. If set, the
                                horizontal axis starts at the first recorded sample
                                instead of time 0.0.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-F</option></term>
                                <term><option>--no-filter</option></term>
                                <listitem><para>Disable filtering of 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
                                0.001 s) will not be displayed in the output graph.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-C</option></term>
                                <term><option>--cmdline</option></term>
                                <listitem><para>Display the full command line with arguments of processes,
                                instead of only the process name.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-g</option></term>
                                <term><option>--control-group</option></term>
                                <listitem><para>Display process control group
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-o</option></term>
                                <term><option>--output <replaceable>path</replaceable></option></term>
                                <listitem><para>Specify the output directory for the
                                graphs. By default, bootchart writes the graphs to
                                <filename>/run/log</filename>.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-i</option></term>
                                <term><option>--init <replaceable>path</replaceable></option></term>
                                <listitem><para>Use this init binary. Defaults to
                                <command>/sbin/init</command>.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-p</option></term>
                                <term><option>--pss</option></term>
                                <listitem><para>Enable logging and graphing
                                of processes' PSS (Proportional Set Size)
                                memory consumption. See <filename>filesystems/proc.txt</filename>
                                in the kernel documentation for an
                                explanation of this field.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-e</option></term>
                                <term><option>--entropy</option></term>
                                <listitem><para>Enable logging and graphing
                                of the kernel random entropy pool size.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-x</option></term>
                                <term><option>--scale-x <replaceable>N</replaceable></option></term>
                                <listitem><para>Horizontal scaling factor for all variable
                                graph components.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-y</option></term>
                                <term><option>--scale-y <replaceable>N</replaceable></option></term>
                                <listitem><para>Vertical scaling factor for all variable
                                graph components.</para></listitem>
                        </varlistentry>

                </variablelist>


        </refsect1>

        <refsect1>
                <title>Output</title>

                <para><command>systemd-bootchart</command> generates SVG graphs. In order to render those
                on a graphical display any SVG capable viewer can be used. It should be
                noted that the SVG render engines in most browsers (including Chrome
                and Firefox) are many times faster than dedicated graphical applications
                like Gimp and Inkscape.  Just point your browser at <ulink url="file:///run/log/" />!
                </para>
        </refsect1>

        <refsect1>
                <title>History</title>

                <para>This version of bootchart was implemented from
                scratch, but is inspired by former bootchart
                incantations:</para>

                <variablelist>
                        <varlistentry>
                                <term><emphasis>Original bash</emphasis></term>
                                <listitem><para>The original bash/shell code implemented
                                bootchart. This version created a compressed tarball for
                                processing with external applications. This version did
                                not graph anything, only generated data.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><emphasis>Ubuntu C Implementation</emphasis></term>
                                <listitem><para>This version replaced the shell version with
                                a fast and efficient data logger, but also did not graph
                                the data.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><emphasis>Java bootchart</emphasis></term>
                                <listitem><para>This was the original graphing application
                                for charting the data, written in java.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><emphasis>pybootchartgui.py</emphasis></term>
                                <listitem><para>pybootchart created a graph from the data
                                collected by either the bash or C version.</para></listitem>
                        </varlistentry>
                </variablelist>

                <para>The version of bootchart you are using now combines both the data
                collection and the charting into a single application, making it more
                efficient and simpler. There are no longer any timing issues with the data
                collector and the grapher, as the graphing cannot be run until the data
                has been collected. Also, the data kept in memory is reduced to the absolute
                minimum needed.</para>

        </refsect1>

        <refsect1>
                <title>See Also</title>
                <para>
                        <citerefentry project='man-pages'><refentrytitle>bootchart.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                </para>
        </refsect1>

        <refsect1>
                <title>Bugs</title>
                <para>systemd-bootchart does not get the model information for the hard drive
                unless the root device is specified with <code>root=/dev/sdxY</code>. Using
                UUIDs or PARTUUIDs will boot fine, but the hard drive model will not be
                added to the chart.</para>
                <para>For bugs, please contact the author and current maintainer:</para>
                <simplelist>
                        <member>Auke Kok <email>auke-jan.h.kok@intel.com</email></member>
                </simplelist>
        </refsect1>

</refentry>
