[systemd-devel] slow uefi firmware/boot

[Damien Robert]

I apologize for the out of topic question, but since systemd-analyze
incorporate the firmware boot time I wonder if you may have any trick to
share in order to improve it.

Here is my boot timing (using systemd-boot and a lz4 compressed initrd):

$ systemd-analyzed
Startup finished in 14.156s (firmware) + 1.098s (loader) + 7.473s (kernel)
+ 2.608s (initrd) + 1.766s (userspace) = 27.103s

I have a few questions on how to improve things:
- obviously for the firmware time there is not much to do except maybe try
  to turn off some uefi autodiscovery settings
- the loader is perfect, I have configured it with 1s delay for the menu
- I am surprised by the kernel time. What does it include?
- the initrd time is fast but I am surprised too that it is slower than
  userspace [but I guess it is because of the mounting of / which also
  mounts /home as a subvolume]. 
  The initrd is also handled by systemd, so the switch root is
  done by initrd-switch-root.service which calls
  /usr/bin/systemctl --no-block --force switch-root /sysroot
  I don't know how much information is transmitted during this switch,
  is there a 'systemd-analyze blame' I could do to see the time spent in
  the initrd (without using bootchart)?

Thanks!