NAME

       systemd-bootchart - Boot performance graphing tool

DESCRIPTION

       systemd-bootchart 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 init=/lib/systemd/systemd-bootchart on the kernel command line,
       adding initcall_debug to collect data on kernel init threads. systemd-bootchart will then
       fork the real init off to resume normal system startup, while monitoring and logging
       startup information in the background.

       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 systemd-analyze plot function.

       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 --rel switch in this case.

       Bootchart does not require root privileges, and will happily run as a normal user.

       Bootchart graphs are by default written time-stamped in /run/log and saved to the journal
       with MESSAGE_ID=9f26aa562cf440c2b16c773d0479b518. Journal field BOOTCHART= contains the
       bootchart in SVG format.

INVOCATION

       systemd-bootchart can be invoked in several different ways:

       Kernel invocation
           The kernel can invoke systemd-bootchart instead of the init process. In turn,
           systemd-bootchart will invoke /lib/systemd/systemd. Data will be collected on kernel
           init threads and also processes including the services started by systemd.

       systemd unit
           A unit file is provided, systemd-bootchart.service. If enabled when the system starts
           it will collect data on processes including the services started by systemd.

       Started as a standalone program
           One can execute systemd-bootchart as normal application from the command line. 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. The time elapsed since boot might also include any time that
           the system was suspended.

OPTIONS

       These options can also be set in the /etc/systemd/bootchart.conf file. See
       bootchart.conf(5).

       -h, --help
           Print a short help text and exit.

       -n, --sample N
           Specify the number of samples, N, to record. Samples will be recorded at intervals
           defined with --freq.

       -f, --freq f
           Specify the sample log frequency, a positive real f, in Hz. Most systems can cope with
           values up to 25-50 without creating too much overhead.

       -r, --rel
           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.

       -F, --no-filter
           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.

       -C, --cmdline
           Display the full command line with arguments of processes, instead of only the process
           name.

       -g, --control-group
           Display process control group

       -o, --output path
           Specify the output directory for the graphs. By default, bootchart writes the graphs
           to /run/log.

       -i, --init path
           Use this init binary. Defaults to /lib/systemd/systemd.

       -p, --pss
           Enable logging and graphing of processes' PSS (Proportional Set Size) memory
           consumption. See filesystems/proc.txt in the kernel documentation for an explanation
           of this field.

       -e, --entropy
           Enable logging and graphing of the kernel random entropy pool size.

       -x, --scale-x N
           Horizontal scaling factor for all variable graph components.

       -y, --scale-y N
           Vertical scaling factor for all variable graph components.

OUTPUT

       systemd-bootchart 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 file:///run/log/!

HISTORY

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

       Original bash
           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.

       Ubuntu C Implementation
           This version replaced the shell version with a fast and efficient data logger, but
           also did not graph the data.

       Java bootchart
           This was the original graphing application for charting the data, written in java.

       pybootchartgui.py
           pybootchart created a graph from the data collected by either the bash or C version.

       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.

SEE ALSO

       bootchart.conf(5)

BUGS

       systemd-bootchart does not get the model information for the hard drive unless the root
       device is specified with root=/dev/sdxY. Using UUIDs or PARTUUIDs will boot fine, but the
       hard drive model will not be added to the chart.

       For bugs, please contact the author and current maintainer:
           Auke Kok <auke-jan.h.kok@intel.com>