mjhjmtu

I am trying to reduce startup time of a Beaglebone (4.14.32-ti-r42 #1 SMP Thu Apr 5 23:13:09 UTC 2018 armv7l GNU/Linux) running Debian Stretch to display a local HTML page on its LCD.

Every analysis I've done so far indicates startup is <25s, but it still takes over 45s to display the HTML page.

systemd-analyze
 Startup finished in 6.158s (kernel) + 17.082s (userspace) = 23.240s

systemd-analyze blame
 22.762s dev-mmcblk1p1.device
 12.823s postgresql@9.6-main.service
 2.613s systemd-udev-trigger.service
 2.301s systemd-logind.service
 1.874s sysstat.service
 1.848s networking.service
 1.431s bb-wl18xx-wlan0.service
 1.430s ssh.service
 1.186s generic-board-startup.service
 1.082s connman.service
 891ms avahi-daemon.service
 859ms systemd-journald.service
 798ms udhcpd.service
 639ms systemd-udevd.service
 491ms systemd-timesyncd.service
 464ms systemd-random-seed.service
 449ms systemd-tmpfiles-setup-dev.service
 415ms systemd-user-sessions.service
 363ms rsyslog.service
 310ms systemd-sysctl.service
 304ms sys-fs-fuse-connections.mount
 302ms systemd-update-utmp-runlevel.service
 302ms systemd-tmpfiles-setup.service
 269ms sys-kernel-debug.mount
 269ms hostapd.service
 252ms sys-kernel-config.mount
 249ms systemd-modules-load.service
 230ms systemd-backlight@backlight:backlight.service
 221ms systemd-journal-flush.service
 215ms dev-mqueue.mount
 205ms kmod-static-nodes.service
 205ms systemd-update-utmp.service
 199ms user@1000.service
 160ms systemd-remount-fs.service
 47ms postgresql.service

systemd-analyze critical-chain
graphical.target @14.388s
└─multi-user.target @14.383s
 └─postgresql.service @14.326s +30ms
 └─postgresql@9.6-main.service @3.885s +10.382s
 └─basic.target @3.639s
 └─sockets.target @3.639s
 └─dbus.socket @3.639s
 └─sysinit.target @3.635s
 └─systemd-backlight@backlight:backlight.service @12.982s +205ms
 └─system-systemdx2dbacklight.slice @12.943s
 └─system.slice @700ms
 └─-.slice @614ms

The HTML page service

The process I created that loads the page on the LCD is at-gui.service:

[Unit]
Description=Start GUI

[Service]
ExecStart=/bin/bash -lc 'startx'

[Install]
WantedBy=basic.target

This process starts OpenBox, which is configured to load a browser with the HTML page shown.

Startup Times

The LCD shows some change in brightness (potentially indicating Openbox has started?) around 27s after startup. It takes 48s to show the HTML page.

A possible start

• The item postgresql@9.6-main.service takes >10s to start. I need it (I need access to a Postgres database), but not before showing that first page. Is there a leaner equivalent of postgresql@9.6-main.service just for running a Postgres database?

Main question

• How can one see where the extra ~25s is going?


• How can one front-load the display of an HTML page?

To answer your first question:

Your at-gui.service has Type=simple (the default), so it's considered started as soon as the bash process is started. Thus whatever time it actually takes for it to display something useful is not accounted for by systemd.

I don't understand your second question, and it should probably be asked separately anyway.