[bee_rider]

You can see what is eating up the time as you boot if you use SystemD.

https://wiki.archlinux.org/title/Improving_performance/Boot_...

I haven’t really had any issues with Linux boot times for personal machines lately. I think the people that care most about getting into the sub-second range are the ones doing cloud VM stuff, spinning up lots of micro services or whatever.

[jeroenhd]

My computer takes about 45 seconds to start, which isn't terrible, but when I run a Windows XP VM on a quarter of the CPU cores I'm reminded of how long those 45 seconds are.

Even without the stupid 20 seconds of firmware I can't do anything about, XP shows me an interactive desktop in half the time Linux does. Windows 7 is just as fast, and just as fully-featured as my desktop Linux install. Windows 11 still boots faster (and more reliably) than Linux despite the overhead of Windows Defender and drive signature checking.

I don't need 0.3 seconds of boot time on my desktop, but something a bit faster would be nice. I think my machine is so slow by the death of a thousand services all starting at boot.

[akho]

Yeah, that’s way too long. My laptop (intel gen11) spends ~7s on firmware, a while in kernel (can’t tell how much of that is me typing my excessively long LUKS passphrase; last boot was 11s, of which waiting for me to type was probably at least 5s…), and just 2.2s in userspace before reaching graphical.target (i.e. I get a GDM prompt). If my assumption on my typing speed is right, OS takes no longer than firmware + bootloader.

(~0.2s is wasted on a dependency that shouldn’t be there, but I’m not prepared to resolve that)

[jeroenhd]

My laptop beats my PC in boot times, but also has a tendency to freeze/panic whewn switching to GDM, and when I force reboot it'll freeze a few times in a row and then work again (it's either an Nvidia problem or an Intel problem, but I don't get any stack traces because the display is frozen). 10th gen laptop versus 7th gen desktop seems to make quite a difference.

Linux definitely can be fast, but in my experience it starts slowing down as you install more services and tools, and I'd need to reinstall and reconfigure from a clean slate to get back to normal speeds. I can make it quick again ny disabling a ron of services and features, but that just slows me down later in the process.

[akho]

> Linux definitely can be fast, but in my experience it starts slowing down as you install more services and tools

There's a weird tendency to put things into multi-user.target to have them run at boot, even if they are not actually required for user login. There's no actual need to start openssh before gdm, but that's how distros set things up.

[jeroenhd]

That's true, but I don't think GDM actually cares about OpenSSH.

On my machine (which I didn't alter from Ubuntu defaults) GDM runs after:

    system.slice switcheroo-control.service dbus.socket plymouth-quit.service console-setup.service cloud-config.service gpu-manager.service rc-local.service systemd-journald.socket systemd-user-sessions.service basic.target plymouth-start.service [e-mail] fwupd.service sysinit.target

according to systemctl show gdm.service --property=After

cloud-config is the weirdest one, but it has to do with locales and system configurations for automatically deployed systems (and after first install), I believe. [e-mail] is also strange, but doesn't even show up in systemd-analyze blame.

In my boot-analyze charts I don't really see that many problems with illogical start orders to be honest. systemd-networkd-wait-online seems to hold up a bunch of networking services but that depends on the rest of my network responding in time so I can't even blame it for that.

[bee_rider]

Have you tried running

    systemd-analyze

And then

    systemd-analyze critical-chain

To see what is slowing it down?

My system takes 10 seconds to boot apparently, with fairly minimal tuning (I boot from a USB drive so I try not to worry too much about this, hah!). But I don’t use a desktop environment or any of that sort of stuff, so it is probably not a good comparison.

Still, 45 seconds is pretty slow, I wonder if it is waiting for something that idles out; network interfaces or something like that.

[jeroenhd]

20 seconds in firmware, 8 in kernel, 6 seconds waiting for systemd networks to load, a second for Docker and an encrypted LUKS drive are most of my boot process (and a thousand tiny systemd services, of course).

I can disable a few things here and there, but whatever hardware detection takes place in the kernel (I assume Nvidia related things, it's always Nvidia it seems) isn't really somethint I can change. I can try disabling more POST parts, maybe, and disable Docker on boot to take off another second, but to shave everything down I'll probably need to reinstall.

[bee_rider]

Your original post (which, I assume, was just kind of an off the cuff guess, so I’m not trying to “gotcha” here), had us at around 25 seconds in kernel+user. So the goal of half that is around 12.5 seconds. And you measured 14 seconds. So it seems like it is in the right ballpark? I can save about a second by disabling NetworkManager… I’m sure there’d be some way to defer it, but it is not worth playing with it IMO.

Out of curiosity did you do some tuning or was the boot just faster than you guessed (if it is the latter, let’s all celebrate the fact that our computers have gotten fast enough to confuse us, haha! When XP actually came out I was a teenager with junky hand-me-down hardware, 45 second boots would have been a dream…).

[jeroenhd]

systemd-analyze plot gives me the following numbers:

Startup finished in 17.642s (firmware) + 9.467s (loader) + 20.168s (kernel) + 12.175s (userspace) = 59.453s graphical.target reached after 12.102s in userspace.

Subtract the slow motherboard firmware (17.642s) and me typing in my password (about 5s, nowhere close to the 9s+20s that the loader+kernel is taking to boot before systemd kicks in) and I get about 45 seconds of "this is what Linux and tools is actually doing before I can log in".

All Windows version from XP up to 7 were horrifically slow until modern SSDs came along. For years, you could take any Vista (or even XP) era computer, double or quadruple the RAM and insert an SSD, and it would feel like a completely new machine. You can still pick up a second hand high-end Windows 7 computer for cheap and use it for what you would otherwise spend $500-700 dollars on after ripping out the hard drive and installing an SSD.

Having used Windows 7 from a HDD for years, I can tell you for sure that Windows 7 sure didn't boot this fast when I first got it :)

[xp84]

Idk your specifics, but modern Windows also essentially hibernates a clean memory state image before login and resumes from it anytime it does a cold boot (it discards it and does a “real” boot when you explicitly Restart). So that seems to be one way it gets a leg up in this contest.

[jeroenhd]

I know, but I've disabled most fast boot tricks because rebooting into Limux became an issue.

It's a cool trick that reminds me of Firecracker. It would be nice to see Linux use that trick as well, but with the existing issues for Linux ×+ hibernation + lockdown mode, I think it'll take a while before that's finished.