Boot time/memory comparison: sysvinit vs systemd

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Re: Boot time/memory comparison: sysvinit vs systemd

Postby confuseling » 2015-02-02 13:59

wizard10000 wrote:...
On a server I really wouldn't care about a few seconds of boot time and to be honest I don't care much about it on my laptop either. If someone is bouncing a server often enough for a couple seconds boot time to even factor into an init system either their server's broken or they're a really poor sysadmin :)

Same with my personal machine, which only gets rebooted during kernel upgrades for the most part.


I've heard it argued that small improvements in boot times are very important to virtualised server farms, where you might be spinning hundreds (or thousands) of images up depending on demand.

But yeah, for my laptop and my Raspberry Pi, the difference between 10 seconds and 1 minute is basically meaningless...

Phones and in-vehicle entertainment etc., on the other hand, are another area where people care.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby wizard10000 » 2015-02-02 14:58

confuseling wrote:I've heard it argued that small improvements in boot times are very important to virtualised server farms, where you might be spinning hundreds (or thousands) of images up depending on demand.


Maybe, but generally you don't stick more than two or three dozen servers under a single host; and I can't think of a situation outside of a catastrophic datacenter loss where you'd be booting them all at the same time :)
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby mardybear » 2015-02-02 15:43

Boot time is such a silly sell or welcomed side effect...and systemd doesn't seem to make much of a difference anyway. Using the same hardware, my busybox-based installs have booted to desktop before sysvinit even gets to the display manager login. That's just me using a desktop though, i'm no system administrator. Just IMO, lean and simple is generally better, not adding extra layers of complexity.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby thenewguy » 2015-02-05 15:25

NkfzGx3ok wrote:
thenewguy wrote:Seems weird when projects like openSUSE and Fedora claimed they switched init technology in large part because of the difference in boot times.

Have any official links to any of that? I've been around systemd and the discussion in Fedora and SUSE since 2010 and the speed has always been a welcome side effect and never a tier 1 reason.

thenewguy wrote:Looking over the systemd website, the claims about systemd being faster seem to have been removed. I think everyone is now aware (or at least they should be) systemd is not faster.

Again, citation, please? You can use archive services to go back and view the pages and get links. AFIAK in the past 5 years systemd has never been marketed it's developers or distros devs because of speed (again, just a nice side effect), that is an end user argument flung around the net because visually that is the only noticeable difference.


Oh, and to be on topic, one of our debian test servers:
Code: Select all
# Startup finished in 1.489s (kernel) + 2.015s (initrd) + 1.838s (userspace) = 5.342s


Someone else already replied with the link to openSUSE's notes on systemd supposedly being faster. Here is a link to Debian's debate on systemd where the same claim is made: https://wiki.debian.org/Debate/initsyst ... to_systemd
And here is the link to where Fedora makes the same claim: https://fedoraproject.org/wiki/Features/systemd
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby NkfzGx3ok » 2015-02-05 16:22

thenewguy wrote:Someone else already replied with the link to openSUSE's notes on systemd supposedly being faster. Here is a link to Debian's debate on systemd where the same claim is made: https://wiki.debian.org/Debate/initsyst ... to_systemd
And here is the link to where Fedora makes the same claim: https://fedoraproject.org/wiki/Features/systemd


Let's keep the following which you said in mind:
thenewguy wrote:Seems weird when projects like openSUSE and Fedora claimed they switched init technology in large part because of the difference in boot times.


https://wiki.debian.org/Debate/initsyst ... to_systemd
"Systemd is incredibly fast (1 second to boot). It was not designed with speed in mind, but doing things correctly avoids all the delays currently incurred by the boot process."
5th bullet point on the list, doesn't seem very 'switching init technology for speed'-y to me.

https://fedoraproject.org/wiki/Features/systemd
"Note that in the long run systemd will provide quicker boot up, but completing that will take more work, since some additional changes to our early boot-up need to take place such as splitting up rc.sysinit. However the focus of systemd is primarily doing things right, and not exclusively on speed."
Final note half way down the page, even goes in to add clarification. Doesn't seem very 'switching init technology for speed'-y to me.

https://news.opensuse.org/2011/12/22/sy ... suse-12-1/
"systemd – boot faster and cleaner with openSUSE 12.1"
Attention grabbing headline, mentions other things than just speed but I can see it, kinda.

"It comes with many new features like socket and dbus-activation, use of cgroups (control groups) and aggressive parallelization capabilities which leads to a faster boot-up of the system."
First actual mention in the article, goes in to technical details and a lists speed as a benefit users may notice, doesn't seem very 'switching init technology for speed'-y to me.


====
Just to add: I'm not sure what any of these user facing articles/wiki entries have to do with the mass of internal talks/debates that were had across irc and mailing lists between developers and contributors [that lead to systemd being made default in all those distros years ago].

Almost forgot, I am still waiting on:
thenewguy wrote:Looking over the systemd website, the claims about systemd being faster seem to have been removed. I think everyone is now aware (or at least they should be) systemd is not faster.

Do you have the archive links so we can see when and what was removed, please?
====
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Deb-fan » 2015-02-06 08:57

Judging by what many people have said, mainly and mostly Arch linux users, have to conclude it is faster and parallelizing bootup, one of the advantages claimed. However ... brings me to the next point/question. Which version was used here ? The one in testing and unstable is like 3.15, don't quote me on this, think last time checked the one in experimental was 3.18 and in Arch it's no doubt or almost no doubt, whatever is the lastest version of systemd.

Think common sense dictates that bugs were found and squashed and/or features added between 3.15 and .18 ? Again that would just be a reasonable assumption imo. When a newer version is released, makes sense something would be different and hopefully better in it.

One of Arch linux's trademark, the whole our distro is cutting edge latest thing. Back when did try Arch, yeah I liked it and had no problem admitting it can be great, though readily admit Debian is great imo/experience too. Had a minimal Sid install and an Arch install side-by-side and from what I saw 1st hand, sometimes I'd check the unstable repos and compare what was avail in the Arch community repos. Sometimes the versions avail would be the same, sometimes Arch would have newer, sometimes Debian would.

(Edit: nope self-correction on the above, had the Deb experimental repo enabled in that case, am almost sure anyway and don't/didn't like the idea of using it often.)

Also both have additional repo's someone who wants to can enable, Arch has a few, one option being the AUR and really Debian does already have an equiv to it. That being Debian-based Sid distro's, who are 100% Debian compatible that maintain and patch software that may not be avail in Debs software repos, shrugs. For me personally in Arch the community repo was good enough and in Deb/Sid, didn't really want to mess w experimental often either.

Not to mention the tons of other ways someone can get access to newer or even exotic packages not readily avail in a Deb repo. Just saying, judging by the feedback of quite a few Arch users, too many keep harping about a very noticeable boot time improvement for me to believe they're all fulla-chit, more shrugs.

Another thing that occurs to me, there are several other outside factors that could improve or degrade init whether someone is talking about sysv or systemd( for that matter OS function overall PERIOD, including all sys resources o course), not going to bother listing all of the chit-ton of them. If ya don't know, then ya don't, google, experiment and learn all the ways to tweak and enhance a gnu/Linux OS = any distro. With some know how a person can get an outdated system, booting faster than a much higher spec system that's in the hands of an incompetent user. Within reason of course, not talking about an SSD w a dual-quad core vs a 512mb ddr2 w a P4 cpu. ;)

For me though, definitely have more important things to do, than sit in front of a pc w a stop watch anyway. By this pt ... couldn't care less what init system anonymous nixers prefer, for whichever reasons. :D

Jessie hasn't even gone stable, so which version of systemd it'll come w default isn't set in stone. Nor is the gazillion other easy options people have availabe to them, to use something else. For sure 100% it's all about choice, application and skillset. Have absolutely nothing against people using whatever they prefer.

Edit2: Oops cr&p, another thanks to the OP, is interesting and to other community members who shared opinions/insights too.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Deb-fan » 2015-02-06 10:02

Dang it ... just when I thought was safe to go back in the water ! Some more comments about this bs popped into head. *hears everyone in the community cheering, lmao ... Stop ya bytching it'll only take a min peeps. :D

There are several systemd specific tweaks I'm aware of and some for sysvinit too for that matter. So systemd out-of-box, even latest version vs latest and tweaked, yanno ? As for which bottomline would prove faster, on desktop usecase or xyz other application ... Am not interested enough to bother finding out, shrugs. Also not curious enough to ever do a custom minimal Deb w latest systemd vs an Arch w same comparison either. If someone linked to a credible one ... will be happy 2 click on it though. ;)

Also hardware specs do play a role, think it's reasonable to assume also that many Arch users aren't just concerned with latest shiny software versions, don't doubt quite a % of them are also obsessed w the latest shiny hardware to run their latest shiny software on. :)

GPT+UEFI and a gnu/nix OS installed to fully use them vs outdated bios/mbr hardware thingy. Personally also think it's reasonable to assume all these Arch users trumpeting about how much faster systemd is for them, are using an older Arch install w sysvinit vs an Arch install w systemd default on the same hardware. As tweaked and latest obsessed as many Archers seem to be, I don't doubt @ all, there's 100's of Arch users sitting @ their pc w a stop watch, while am typing this. :P

Last stupe comment, also as several people have already said, boottime isn't all that friggin important me thinks. Many nixers NEVER turn off their personal computers and system admins w a production server(s), unless there's some good reason or they're retarded, shoot for months, even years between reboots, shrugs. So it'd poss be of interest to some gnu/nix desktoppers I guess.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Head_on_a_Stick » 2015-02-06 10:03

@deb-fan (CBizGreat):

Arch is using version 218 ATM and jessie is on version 215 and this will be the release version but it will get bug-fixes so the versioning doesn't tell the whole story.

The main difference between Arch & Debian is that Arch only patches the packages if absolutely necessary, they try to just pass on the upsteam source if at all possible.

Debian OTOH love a good patch -- this can be a good thing as sometimes packages will work in Debian sid but not in Arch (especially stuff like GNOME-shell).

As for the boot times, I think the OP is right in this case -- I really can't tell much difference between SysVinit & systemd on my sid system.

The main difference for me is that I find it much easier to control and (in particular) query & troubleshoot running services and daemons under systemd.

Of course this may be because I don't know what I'm doing when it comes to SysVinit...

Also, I have to say that I prefer the BSD/Slackware-style booting system over SysVinit -- again just because I find it easier to control stuff.

Of course that's just my opinion and I'm still very much a GNU/Linux n00b.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Deb-fan » 2015-02-06 10:27

Yeah knew about ( and forgot the whole vanilla packages aspect of Arch), long since quit caring what Arch is doing, though still look over the awesome wiki the distro has. Your input is always valued by me, HOAS regardless.

Think Sid repo has 3.15 too ? So again, if you feel adventurous and have a testing partition handy, might try adding and pinning Deb experimental and pulling in 3.18 from it on a Sid clone ? Though wouldn't blame ya a bit if ya just gave me the finger and said nope, not spending the time. Also ... as commented above, there are tweaks for systemd. Lol ... you're going to google it now, I know ya are fellow nixer. :D

Bottomline ... jmo/preference, still feel more comfortable w Debian, than I would w Arch and yeppers as mentioned elsewhere being on the "cutting edge" can get people cut, be a good or bad thing depending. Though whatever gnu/nix setup someone has, if they learn enough skills or are one of those blessed with common sense. They have little to worry about.

A nixer I respected gave me the following advice, when I mentioned hey I'm going to install and start screwing w Arch linux. Dude said ... KISS man, don't get carried away w stuff like KDE or Gnome in Arch, unless you like unborking stuff often. :) Which hey, not saying Kde/Gnome are bad ... Full ( bloated)DE's aren't my style anyway. So Arch ran great, up till I told em, close my Arch forum acct, I'm sticking w dear Debian. :D

Oops, PS,

Shhhhhhh I'm undercover. ;)


EDIT!Arghhh! Also agree w you, things like whatcha mentioned are definitely more important, than stupe boottime imo too. We don need no stupid boottime ! Though it'd be alright if systemd can provide that, along w more important stuff, shrugs.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Ibidem » 2015-02-21 03:16

Head_on_a_Stick wrote:The main difference for me is that I find it much easier to control and (in particular) query & troubleshoot running services and daemons under systemd.

Of course this may be because I don't know what I'm doing when it comes to SysVinit...

Also, I have to say that I prefer the BSD/Slackware-style booting system over SysVinit -- again just because I find it easier to control stuff.

Of course that's just my opinion and I'm still very much a GNU/Linux n00b.


Perhaps you'd like sysvinit + file-rc ?

openrc has been fairly nice for troubleshooting in my experience, but I haven't used it with Debian.
Got a pretty fast boot using it with Alpine Linux; much faster than the LFS bootscripts I used on my own system..I'm tempted to replace that with a done-from-scratch set of scripts.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Deb-fan » 2017-03-31 19:31

Not willing to invest the time to do side-by-side on my system. Will take others here at their word but boot time is only 1 metric and imo not a very important one, considering many of us nixers go for extended periods between reboots. :) Even on personal, let alone production systems.

However things like the ability to properly utilize cgroups, track forked processes and restart crashed processes/services should be considered important me thinks.

Pointless 2 cents.
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Re: Boot time/memory comparison: sysvinit vs systemd

Postby Nili » 2017-04-01 07:12

My investigation on a 10-years-old desktop

Code: Select all
ps --no-headers -o comm 1

init

Boot 8.0sec
Memory: X > 25MB +1.9MB > startx = 26.9MB

Code: Select all
ps --no-headers -o comm 1

systemd

Boot 8.8sec
Memory: X > 28MB+ 2.1MB > startx = 30.1MB

The difference is visible on me but not anything big. Both are fast on my old-grey desktop.

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Re: Boot time/memory comparison: sysvinit vs systemd

Postby debiman » 2017-04-01 07:21

comparing boot times, all i can say is that i remember boot times de-creasing dramatically after i changed from a sysvinit-based distro to a systemd-based one.
neither system had any tweaking done to improve init stuff.

i switch my desktop computer on/off daily, and hibernate the other one, so for me it matters.

but please don't misunderstand my post for "i'm a systemd fanboi because it boots faster".
i'm not a fanboi and boot time is just one of many aspects.
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