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Analyzing boot performance of OpenSuse 11.1 with bootchart

Often the boot process of a machine is not as fast as one would like. It is commonly suggested that you reduce the number of started services so that your machine boots up faster. However, one thing we must know before trying to optimize our boot process, is where it is slow. To do that, we will use a tool called bootchart.

Bootchart is a tool for performance analysis and visualization of the GNU/Linux boot process. Resource utilization data and process information are collected during the boot process, and can later be displayed in a PNG, SVG, or EPS encoded chart. Analyzing the chart will help in finding opportunities for optimization.

The first thing we must do is, obviously, install the package, open yast -- software managment and search for "bootchart" and click on "Accept" to install bootchart

Bootchart provides a shell script to be run by the kernel in the init phase. The script will run in background and collect process information, CPU statistics and disk usage statistics from the /proc file system. The performance data are stored in memory and are written to disk once the boot process completes.

The boot log file is later processed using a Java application (or the web form) which builds the process tree and renders a performance chart in different formats.

Bootchartd mounts a tmpfs below /tmp, so make sure you don't clear this at boot time, otherwise you will have invalid data.

Especially check the setting of: CLEAR_TMP_DIRS_AT_BOOTUP in sysconfig/cron

Reboot your system and after reboot you will find two files (bootchart.tgz and bootchart.png) under /var/log directory and this png file will give you detail view of the time that a particular process has taken while booting so that you can look into it and can optimize it for faster booting.


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