Boot time speedup

General Discussion
21

That did it, I can now ssh in via usb. Wahoo I 'm now a Linux kernel developer, fame and fortune awaits.

Thank you very much!

22

I have taken a couple of seconds off the kernel boot time now. Also removed about 10 services by stop, disable and removing their file from /etc/systemd/system and /usr/lib/systemd/system also used apt remove where needed. according to the svg plot the rest of the services take minimal time to execute.
Now I need to reduce the userspace boot time. Userspace is taking 25.6 seconds.

  1. How is the userspace booting up, where the file controlling that process.
  2. What can be removed to make userspace boot faster?
  3. when does user code start to be executed, when is /etc/init.d at the end of userspace boot time?
23

I had boot time issues with 11.8 kernel 5.10.168-ti-r71. Not sure which kernel is in image you are using.

I found this patch to kernel saved 6 seconds in booting.
https://patchwork.kernel.org/project/linux-acpi/cover/20201121020232.908850-1-saravanak@google.com/#23791353

24

Thank you for that link. I have no idea how to get it though. Is that for buildroot or guys who are compiling their own Linux from source? Looks to me like they are compiling their own.

25

Yes I had to rebuild the kernel from source with that patch. I have an image here if you want to see if it does anything for you.

http://www.pdp8online.com/mfm/revb/software.shtml

I cross compiled on Fedora. I can give you the build tree also if useful.

26

Thank you again, it is very helpful. I would like to see your build tree too. I am new at this and I very much want to learn how to build my own Linux kernel for the BBB. Learning from others is great, maybe someday I can contribute back some knowledge.

27

Looks like I started with kernel 5.10.168-ti-rt-r74.tar.gz

My cryptic notes on building the kernel
https://www.pdp8online.com/misc/kernel-build. I don’t do this often so this was looking at web pages until I found something that worked.

Tree here
https://www.pdp8online.com/misc/patched-linux-5.10.168-ti-r74.tgz

Sorry for slow response but life is busy right now.

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