systemd-bootchart — Boot performance graphing tool
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=
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.
/usr/lib/systemd/systemd-bootchart
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.
systemd-bootchart can be invoked in several different ways:
The kernel can invoke systemd-bootchart instead of the init process. In turn, systemd-bootchart will invoke /sbin/init.
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.
These options can also be set in the
/etc/systemd/bootchart.conf
file. See
bootchart.conf(5).
-h, --help¶Prints a short help text and exits.
-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.
-o, --output path¶Specify the output folder for the
graphs. By default, bootchart writes the graphs to
/run/log.
-i, --init path¶Use this init binary. Defaults to /sbin/init.
-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.
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/!
This version of bootchart was implemented from scratch, but is inspired by former bootchart incantations:
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.
This version replaced the shell version with a fast and efficient data logger, but also did not graph the data.
This was the original graphing application for charting the data, written in java.
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.
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> |