systemd/man/systemd-bootchart.xml

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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'>
        <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 analysis graphing tool</refpurpose>
        </refnamediv>

        <refsect1>
                <title>Description</title>

                <para>systemd-bootchart is a tool used to analyze a boot sequence.
                It collects system information pertaining to the CPU and disk load, as
                well as per-process information, and then creates a chart with this
                information. Usually it is invoked by setting the init to
                <filename>systemd-bootchart</filename> on the kernel command line. It
                be run after boot to analyze running processes, though it is recommended
                to use the <option>--rel</option> switch when doing this.</para>

                <para>After collecting a certain amount of data (default: 20 seconds) it
                will write the SVG chart to <filename>/run/log</filename>. This chart
                can be used to find problems in the start up sequence and where these
                problems exist. It is essentially a more detailed version of the
                systemd-analyze plot function.</para>

        </refsect1>

        <refsect1>
                <title>Invocation</title>

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

                <variablelist>

                        <varlistentry>
                                <term><emphasis>Kernel invocation</emphasis></term>
                                <listitem><para>The kernel can invoke systemd-bootchart
                                instead of the init process. In itself, systemd-bootchart
                                will invoke <filename>/sbin/init</filename> if invoked in
                                this manner.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><emphasis>Started as a standalone program</emphasis></term>
                                <listitem><para>One can execute systemd-bootchart as
                                normal application from the commandline. In this mode
                                it is highly recommended to pass the "-r" 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.
                                </para></listitem>
                        </varlistentry>
                </variablelist>
        </refsect1>

        <refsect1>
                <title>Options</title>

                <para>These options can be set globally in the <filename>/etc/systemd/bootchart.conf</filename>
                file.</para>

                <variablelist>

                        <varlistentry>
                                <term><option>-n</option></term>
                                <term><option>--sample N</option></term>
                                <listitem><para>Specify the amount of samples, N, to
                                record total before bootchart exits. Each sample will
                                record at intervals defined by --freq.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-f</option></term>
                                <term><option>--freq N</option></term>
                                <listitem><para>Specify the sample log frequency, N.
                                This can be a fractional number, but must be larger than
                                0.0. Most systems can cope with values under 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, otherwise 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>--filter</option></term>
                                <listitem><para>Disable filtering of tasks 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
                                0.001sec) will not be displayed in the output graph.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-o</option></term>
                                <term><option>--output [path]</option></term>
                                <listitem><para>Configures the output folder for writing
                                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 [path]</option></term>
                                <listitem><para>Set init binary to run. Defaults to
                                <filename>/sbin/init</filename>.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><option>-p</option></term>
                                <term><option>--pss</option></term>
                                <listitem><para>Enable logging and graphing
                                of processes PSS memory consumption.</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 N</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 N</option></term>
                                <listitem><para>Vertical scaling factor for all variable
                                graph components.</para></listitem>
                        </varlistentry>

                </variablelist>


        </refsect1>

        <refsect1>
                <title>Output</title>

                <para>systemd-bootchart generates SVG graphs. In order to render these
                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 "file:///run/log"!
                </para>
        </refsect1>

        <refsect1>
                <title>History</title>

                <para>This version of bootchart was implemented from scratch, but 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><refentrytitle>bootchart.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                </para>
        </refsect1>

        <refsect1>
                <title>Bugs</title>
                <para>For bugs, please contact the author or current maintainer:</para>
                <varlistentry>
                        <term>Auke Kok</term>
                        <term><emphasis>auke-jan.h.kok@intel.com</emphasis></term>
                </varlistentry>
        </refsect1>

</refentry>