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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 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</command>

<command>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>.

</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. </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><refentrytitle>bootchart.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.

</para>

<variablelist>

<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>-o</option></term>

<term><option>--output <replaceable>path</replaceable></option></term>

<listitem><para>Specify the output folder 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><refentrytitle>bootchart.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>

</para>

</refsect1>

<refsect1>

<title>Bugs</title>

<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>