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systemd/man/systemd-bootchart.xml
Tom Gundersen 12b42c7667 man: revert dynamic paths for split-usr setups
This did not really work out as we had hoped. Trying to do this upstream
introduced several problems that probably makes it better suited as a
downstream patch after all. At any rate, it is not releaseable in the
current state, so we at least need to revert this before the release.

 * by adjusting the path to binaries, but not do the same thing to the
   search path we end up with inconsistent man-pages. Adjusting the search
   path too would be quite messy, and it is not at all obvious that this is
   worth the effort, but at any rate it would have to be done before we
   could ship this.

 * this means that distributed man-pages does not make sense as they depend
   on config options, and for better or worse we are still distributing
   man pages, so that is something that definitely needs sorting out before
   we could ship with this patch.

 * we have long held that split-usr is only minimally supported in order
   to boot, and something we hope will eventually go away. So before we start
   adding even more magic/effort in order to make this work nicely, we should
   probably question if it makes sense at all.
2015-06-18 19:47:44 +02:00

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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2012 Intel Corporation
Authors:
Auke Kok <auke-jan.h.kok@intel.com>
William Giokas <1007380@gmail.com>
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
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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You should have received a copy of the GNU Lesser General Public License
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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 command line. 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>/usr/lib/systemd/systemd</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 command line. 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>/usr/lib/systemd/systemd</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>