Software Tweak Makes Linux Boot In Under 200 ms

An anonymous reader writes "A version of Linux has been created that radically speeds up system boot time -- to less than 200 milliseconds (ms) from power-up to application code startup. The techniques, created by Real-time Linux vendor FSMLabs, are processor independent, and boot times of under 100 mS are expected in the future." Update: 09/30 01:04 GMT by T : Yep -- both headline and post should have read "ms" (milliseconds) rather than "mS" (milli Siemens); thanks to all the alert readers.

Comments

Only for embedded devices

[Professor_Quail]

This isn't for desktop linux, only for embedded devices.

Re:Only for embedded devices

[danheskett]

Windows does exactly that for its "hibernate" feature. Essentially hardware is returned to a safe state (write operation suspended, etc) and the contents of memory written sequentially to a block of disk space. On boot, a small stub is loaded, which copies the data from disk to memory. Execution resumes at that point. The last thing that Windows does before hibernating is to schedule hardware re-initilization in a short period of time - essentially ensuring that things like sound cards, video cards, USB devices, etc get a "soft" reset when out of the hibernation period.

On a decent reasonable recent PC this takes a few seconds. On my fast AMD box I hit the power button and about 2 seconds later the box is off. Hit the power button again and its back on in about 4 seconds exactly where I left off. If I lost my DHCP lease in the interim it takes another 3-4 seconds for network connections to resume.

But whats best about the changes MS made to Windows XP is the multi-threaded boot process. Other than the kernel load the userland stuff is mostly all multi-threaded even on boot. This means services and whatnot are starting concurrently without waiting for other things to finish. Its somewhat less safe - a failed service could potentially cause others to hang and lock the system and/or cause a reset - however, I've yet to see that problem in the field. The net result is that on a typical AMD/P4 Windows XP box you can get to a login prompt/welcome screen in under 30 seconds, often under 20.

Users I've switched from XP to various Linuxes have all complained about the boot times - Red Hat 8 on similiar hardware takes eons to get a graphical login prompt. SuSE is just as bad. Mandrake is somewhat better, but all are in the minutes not seconds metric.

incredible

[alienhazard]

this is certianly incredible, but it is not yet available for x86 platforms. Do note, that this is not the boot sequence up till you get the login prompt, but just the initial loading of the kernel.

kernel boot != complete system initialization

[Ankh]

Note that for embedded systems the main interest is how long it takes for the kernel to load, not how long it is before a multi-user server or workstation has a prompt that says "login" on a pretty X display.

So, this is a good improvement it seems, but shaves away 4.5 seconds or so out of maybe 30 sconds or over a minute for many people. Combined with the parallel init scripts work mentioned a few days ago,though, I'm guessing that Linux systems will be booting a lot faster with the major releases in 6 months to a year.

Re:Slightly off topic but about *nix boot times

[gordyf]

Linux starts its services before it brings up the password prompt. Windows loads, displays the login prompt and continues starting services in the background.

Booting Linux Faster through Blocking

[Eponymous Cowboy]

Although this article refers to embedded systems, the earlier Booting Linux Faster article contained an overlooked post by TornSheetMetal, who had a great idea on how to make Linux, or any operating system start up faster on any system.

Simply run every startup script simultaneously, but have each script block until its dependencies have started. Nothing waits longer than it needs to, and there is no need for additional complex systems to check and manage dependencies.

This is VERY easy to do with daemontools and svok (both written by D.J. Bernstein, the author of qmail). Switch over and you'll never go back.

Re:Booting Linux Faster through Blocking

[targo]

imply run every startup script simultaneously, but have each script block until its dependencies have started.

Btw, this is pretty much what Windows XP does, that's how it achieves a much better boot time compared to earlier Windows versions.

Re:Booting Linux Faster through Blocking

[Anonymous Coward]

That's why it is necessary to do what Windows XP does: each time it boots, it records the order of sector accesses. Then, when it is later idle, it reorganizes those sectors to optimize them for the next boot--a much smarter form of the traditional "defragmentation." The result is a recursive iteration to the optimal sector organization, and the fastest possible boot. (Incidentally, it also does this while loading each individual application, which is why applications start so much faster under XP than 2000.)

Re:NOT Only for embedded devices RTFA

[jonadab]

Nevertheless, it's clear in the article that we're only talking about
kernel boot time here (which is usually about five seconds). The
_other_ three hundred seconds your system spends booting (starting
all the services and stuff, then X, then your desktop environment,
then any apps) are unaffected.

And everyone knows...

[Kashif Shaikh]

...Windows might boot faster, but as we all know windows has D.S.S. capabilities which means "Delayed Service Startup":)

In other words, it loads everything AFTER you login, no joke;)

Re:as if

[robberbarron]

Uh, a Palm pilot doesn't boot when you turn it on. It merely comes out of sleep. The only time it boots is when you hit the reset button on the back. Then it takes about 5-10 seconds to boot.

However, there are a lot of embedded devices that do need to boot quickly. Automotive electronics like your radio, Nav-system, etc.. do boot up when you turn on the car, at least today they do.