systemd Developer Auke Kok auke-jan.h.kok@intel.com systemd-bootchart 1 systemd-bootchart Boot performance analysis graphing tool 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 systemd-bootchart on the kernel command line. It be run after boot to analyze running processes, though it is recommended to use the --rel switch when doing this. After collecting a certain amount of data (default: 20 seconds) it will write the SVG chart to /run/log. 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. systemd-bootchart can be invoked in several different ways: Kernel invocation The kernel can invoke systemd-bootchart instead of the init process. In itself, systemd-bootchart will invoke /sbin/init if invoked in this manner. Started as a standalone program 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 be set globally in the /etc/systemd/bootchart.conf file. -n --sample N Specify the amount of samples, N, to record total before bootchart exits. Each sample will record at intervals defined by --freq. -f --freq N 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. -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, otherwise the graph would become extremely large. If set, the horizontal axis starts at the first recorded sample instead of time=0.0. -F --filter 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. -o --output [path] Configures the output folder for writing the graphs. By default, bootchart writes the graphs to /run/log. -i --init [path] Set init binary to run. Defaults to /sbin/init. -p --pss Enable logging and graphing of processes PSS memory consumption. -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 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"! This version of bootchart was implemented from scratch, but 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. bootchart.conf5 For bugs, please contact the author or current maintainer: Auke Kok auke-jan.h.kok@intel.com