I'd like to find out what takes the most time in my boot process from GRUB to the Ubuntu login screen. How can I profile my boot process to find out what's taking so long?


I have never personally used it, but you could try bootchart. It is packaged for Ubuntu, as is a GUI for it, pybootchartgui.

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  • Cool, so now that I've made a chart, how can I tell what's out of place? – Naftuli Kay Jan 30 '12 at 22:01
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    @TKKocheran There's no magic method. The one-word answer is “experience”. Compare with a few other machines. – Gilles 'SO- stop being evil' Jan 30 '12 at 23:17
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    @TKKocheran: If you want to minimze boot time I suggest you disable all unwanted modules and also disable initrd and compile modules not off kernel. – Gigamegs Jan 31 '12 at 7:01
  • @David, this of course, begs the question: of the over 50 modules in my kernel, how can I figure out which ones are needed and not needed? I have a fast 2.4-3.5GHz quad-core processor, a 7200RPM hybrid hard drive, and 8GB of RAM and I'm seeing boot take around 20-30 seconds. Also, what is initrd and how can I disable it? Compiling modules not off-kernel: meaning statically compiling the modules into the kernel? – Naftuli Kay Jan 31 '12 at 7:07
  • @TKKocheran: Your are right off-kernel means statically into the kernel. You can use lspci -t or lspci -vvv to check your hardware. Initrd is a live file system and it's standard in Linux but I didn't needed it since many years. You can disable it even if you don't want to compile everything statically. – Gigamegs Jan 31 '12 at 7:18

You can use bootchart. It creates a profile of the boot process usually an image.

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An easy option for Ubuntu 15.04 and later is:

systemd-analyze blame
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