can everybody provide some material about reducing the time of starting ubuntu in the TX1

i need some information about cutting the system of ubuntu !
can everybody provide some material about reducing the time of starting ubuntu in the TX1

What are your goals, and do you have an example use-case of how the current boot limits those goals?

You could shave maybe 1 second off U-Boot due to an adjustable delay while waiting for the serial console to interrupt…it isn’t much. Then the kernel loads, and almost all of the real opportunity for boot speed occurs then.

It used to be that the kernel starts init, and init gets PID 1, then scripts would be walked through via init to start different stages. Now init runs systemd, and systemd is what walks through (it’s XML instead of scripts, but more configurable).

Probably the “right way” to cut out services via systemd, but that might be a steep learning curve. You can see what services are being run:

sudo systemctl status

You can see a list of targets stepped through during boot by systemd to start services as runlevels progress by looking at “/lib/systemd/system/*.target”. You can then examine the XML files pointed to by the different runlevels. Should you see something in a target or service you don’t need, you can cut it out via custom targets. Look in “/etc/systemd/system/”. Note that defaults are used from “/lib/systemd/system/” unless the same thing is added in “/etc/”…this way you edit and experiment in “/etc/systemd/system/” instead of in the “/lib/” files…simply copy the original from lib to etc, edit the copy, and try it out. Don’t need bluetooth? This might be the place to cut it out…you could cut out packages related to bluetooth…but you may not be certain if it breaks something else in networking.

A large part of boot time might be related to waiting for networks, waiting for graphics, so on. So before anyone can get more specific about how to cut things out for a faster boot you have to define which services you need to keep. After this you must still understand a Jetson is not an embedded appliance with a lot of bloat…it’s a full computer system with a lot more going on than a typical MCU.

There is a whole section of “Kernel Boot Time Optimization” in the L4T R24.2.1 Tegra Linux Driver Package Developer Guide document.