generic-board-startup.service takes a long time to run, contributing to slow boot time.

[Samathy]

Hello,

I'm currently attempting to decrease the boot time of a Beaglebone Black for use in an industrial situation where boot times are important.

Running systemd-analyze plot shows that generic-board-startup service (which i believe runs eventually runs, am35xx_evm.sh) takes a significant time to run, around 4.5 seconds. Upon reducing the sleep statements in am335x_evm.sh and generic-startup.sh I've got this time down to 2.5 seconds but still wish to reduce this time further. Do you have any suggestions?

I have tried disabling this service from starting at all, but this appears to disable the serial console, meaning I am unable to login to the board.

Thanks.

[RobertCNelson]

@Samathy the am335x_evm.sh script goes thru a bunch of options based on how the image is setup. Since you are targeting one setup, you could remove some of that extra's.

For your application, are you using all 3 modes of the usb? serial gadget, network gadget, flash drive gadget?

For example, if your just using the serial gadget, you could remove the call from generic-board-startup and just have g_serial loaded via:

echo "g_serial" > /etc/modules-load.d/g_serial.conf

For the network gadget, hardcode the values we recover from teh at24 eeprom on the i2c bus..

Regards,

[Samathy]

Thanks for the input, I'll look into your suggestions.

Regards,

[troywweber7]

I'm having the same issue, except my boot times are ridiculously excessive.

# systemd-analyze blame 
         38.438s generic-board-startup.service
         36.895s dev-mmcblk1p1.device
         12.458s apt-daily.service
          3.143s loadcpufreq.service
          3.109s systemd-udev-trigger.service
          2.243s networking.service
          1.731s ssh.service
          1.336s pppd-dns.service
          1.293s bb-wl18xx-wlan0.service
          1.289s connman.service
          1.215s systemd-journald.service
          1.055s systemd-logind.service
          1.015s avahi-daemon.service
           927ms dnsmasq.service
           793ms udhcpd.service
           725ms systemd-timesyncd.service
           573ms cpufrequtils.service
           555ms rsyslog.service
           524ms wpa_supplicant.service
           502ms systemd-udevd.service
           419ms systemd-fsck-root.service
           398ms systemd-update-utmp.service
           374ms systemd-user-sessions.service
           371ms kmod-static-nodes.service
           366ms sys-kernel-debug.mount
           324ms systemd-modules-load.service
           318ms sys-kernel-config.mount
           276ms systemd-remount-fs.service
           267ms sys-fs-fuse-connections.mount
           267ms systemd-sysctl.service
           238ms systemd-journal-flush.service
           234ms systemd-tmpfiles-setup-dev.service
           217ms systemd-tmpfiles-setup.service
           203ms hostapd.service
           202ms [email protected]
           183ms systemd-update-utmp-runlevel.service
           161ms systemd-random-seed.service
           141ms bb-wl18xx-bluetooth.service
           137ms dev-mqueue.mount
            85ms systemd-tmpfiles-clean.service

[RobertCNelson]

It's the usb gadget modules...

[troywweber7]

I should also point out that my kernel takes 26 seconds to load even though its written on and running from the eMMC...

$ ssh [email protected] systemd-analyze 
Startup finished in 26.334s (kernel) + 57.971s (userspace) = 1min 24.305s

How do I know which usb gadget modules I am and am not using so I can disable the ones I'm not using?

[troywweber7]

Also @RobertCNelson, just because it is interesting, here is the plot.zip which contains plot.svg from systemd-analyze plot > plot.svg

It's time-consuming, but I'm contemplating starting from a fresh image and taking plot.svg along the way as I set it up from scratch just to see if its something I did...

[RobertCNelson]

@troywweber7 so this is the slow path:

https://github.com/RobertCNelson/boot-scripts/blob/master/boot/am335x_evm.sh#L472-L550

This builds up and provides:

usb-serial
usb-network
usb-flash

Currently, usb-flash can be disabled easily in /etc/default/bb-boot

USB_IMAGE_FILE_DISABLED=yes

https://github.com/RobertCNelson/boot-scripts/blob/master/boot/default/bb-boot

i'd like to factor the other two at some point.

in v4.15.x/v4.16.x i've been trying to make it work when libcomposite is bulit-in to speed things up, but i haven't had any luck yet..

https://github.com/RobertCNelson/boot-scripts/commits/master/boot/am335x_evm.sh

Regards,

[troywweber7]

@RobertCNelson so am I correct in my understanding of those module's purposes? Here is my current understanding:

• usb-serial allows you to ssh log in over the usb?
• usb-network allows the beaglebone to use your computer's internet to update?
• usb-flash allows you to access a portion of flash storage when the board is plugged in via USB?

[troywweber7]

@RobertCNelson and if I don't need any one of those modules, how do I turn them off exactly?

[troywweber7]

By which I mean, disabling flash is easy as you pointed out, but how do I disable the other options? Do I simply comment out the call to am335xevm.sh within the generic-startup.sh script?

[troywweber7]

@RobertCNelson what I decided to do was to comment out the script="am334x-evm.sh" line in the /opt/scripts/boot/generic-startup.sh script and got much quicker boot times. Is there any danger to this other than losing those fancy usb features?

$ systemd-analyze && systemd-analyze blame
Startup finished in 21.062s (kernel) + 12.218s (userspace) = 33.281s
         19.788s dev-mmcblk1p1.device
          3.013s systemd-udev-trigger.service
          2.564s loadcpufreq.service
          2.511s apache2.service
          2.094s networking.service
          1.995s systemd-logind.service
          1.743s ssh.service
          1.733s udhcpd.service
          1.542s bb-wl18xx-wlan0.service
          1.455s pppd-dns.service
          1.102s connman.service
          1.041s systemd-journald.service
           997ms generic-board-startup.service
           782ms systemd-hostnamed.service
           707ms cpufrequtils.service
           613ms avahi-daemon.service
           596ms wpa_supplicant.service
           546ms [email protected]
           507ms systemd-timesyncd.service
           451ms systemd-update-utmp.service
           450ms systemd-random-seed.service
           402ms systemd-tmpfiles-setup-dev.service
           395ms systemd-udevd.service
           339ms rsyslog.service
           328ms systemd-modules-load.service
           322ms sys-kernel-config.mount
           318ms kmod-static-nodes.service
           317ms sys-kernel-debug.mount
           279ms hostapd.service
           270ms systemd-journal-flush.service
           269ms sys-fs-fuse-connections.mount
           256ms systemd-user-sessions.service
           241ms systemd-sysctl.service
           240ms systemd-update-utmp-runlevel.service
           221ms systemd-tmpfiles-setup.service
           220ms dev-mqueue.mount
           188ms systemd-remount-fs.service
           173ms bb-wl18xx-bluetooth.service

Further, is there anything else I should consider doing to cut back the boot time?

[tesorrells]

@troywweber7 What did you do to retain the ssh capabilities after just commenting out script="am334x-evm.sh"?