Port bootchart2 to PostmarketOS, with three patches:
1. Modification of /etc/bootchartd.conf so that the collector
will stop after sshd has started.
2. Python 3.8 compatibility
3. Disable the interactive mode of pybootchartgui.
Use bootchart2 to profile system boot or a running system.
1. Add the bootchart2 package to your device.
2. Add the following kernel command line parameters: initcall_debug
printk.time=y quiet
3. To profile system boot
a. add the following kernel command line parameter: PMOS_BOOTCHART2.
This parameter causes mkinitfs to start /sbin/bootchartd instead of
/sbin/init. /sbin/bootchartd then starts /sbin/init.
b. (optional) modify EXIT_PROC in /etc/bootchartd.conf to define
when the collector is to stop.
c. Boot the system. Approximately 20 seconds after sshd starts
(if using the default value of EXIT_PROC), the collector
will exit.
4. To profile a running system
a. use the command '/sbin/bootchartd start' (as root) to start
profiling
b. use the command '/sbin/bootchartd stop' (as root) to stop
profiling
5. When the collector exits, /usr/bin/pybootchartgui will create
a visualization in /var/log/bootchart.png.
