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Operating Systems Software Linux

How Kernel Hackers Boosted the Speed of Desktop Linux 380

Posted by timothy
from the mild-claims dept.
chromatic writes "Kernel hackers Arjan van de Ven and Auke Kok showed off Linux booting in five seconds at last month's Linux Plumbers Conference. Arjan and other hackers have already improved the Linux user experience by reducing power consumption and latency. O'Reilly News interviewed him about his work on improving the Linux experience with PowerTOP, LatencyTOP, and Five-Second Boot."
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How Kernel Hackers Boosted the Speed of Desktop Linux

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  • by pwnies (1034518) * <j@jjcm.org> on Thursday October 02, 2008 @03:17PM (#25237899) Homepage Journal
    Not only is this an impressive accomplishment, but if this can be applied generically to most distributions then it should present an excellent opportunity for advertisement. Showing how you can boot, check your email, read the latest news, and be done with all you need to have done while a fellow Vista machine is still booting says a lot. Even if we can get most distributions down to 15sec average, it's a huge leap. Grats to these guys.
    • by Anonymous Coward on Thursday October 02, 2008 @03:29PM (#25238083)

      Kudos to you sir, for reducing the time it takes to type congratulations by instead using grats!

    • by Bryansix (761547) on Thursday October 02, 2008 @03:31PM (#25238109) Homepage
      Actually Vista with 4 Gigs of RAM boots pretty quickly. It's once it's up that it is slow.
      • by Anonymous Coward on Thursday October 02, 2008 @03:32PM (#25238127)
        You can boot Vista with only 4 Gigs of ram?
      • My Vista system has 4 GB, and still takes a painfully long time to boot. I don't know what magic your system uses, but I doubt that it's fast compared even to a non-optimized Linux box.

        To speed up startup time, I hibernate my system instead of shutting it down when I'm not using it. But even that's painfully slow — because of that 4GB memory that needs to be restored.

        Vista introduces something called hybrid mode, which is like sleeping, only safer, because there's also a hibernation image, so the stat

        • by DiegoBravo (324012) on Thursday October 02, 2008 @04:45PM (#25239157) Journal

          There is no such thing as end-user-OS-boot-time. It depends a lot on device drivers and system background utilities. For example, some piece of hardware AND some release version of its driver maybe causing your trouble... especially if that hardware is removed and the driver probes a lot of time just to be sure. Same for the AV software doing weird things in order to "secure" the system *before* user interaction... At least in the hardware side, this apply for Linux too.

      • Re: (Score:3, Insightful)

        by Theolojin (102108)

        Actually Vista with 4 Gigs of RAM boots pretty quickly. It's once it's up that it is slow.

        Microsoft seems to have performed a bit of trickery to make you perceive that Vista boots quickly. The desktop on my wife's Vista laptop appears fairly quickly but it is simply unusable for a couple more minutes. This is different from XP which is fairly usable as soon as (well, shortly after) the desktop appears. It's rather like the desktop is the bootsplash on Vista.

        • Re: (Score:3, Interesting)

          I would say XP can also be unusable for a minute or two after login depending on what background applications and drivers start up. Certainly a clean XP install will be usable instantly.
    • by SilentChris (452960) on Thursday October 02, 2008 @03:43PM (#25238289) Homepage

      The only issue is that they had to cut some corners to make this work. Axing sendmail? Ok, I understand that (I think was arguing that 10 years ago -- still don't wonder why that's on by default in the desktop distributions). But "The 'done booting' time did not include bringing up the network"? Um, ok... no. With the proliferation of devices solely used to read information from networks (Netbooks, those "quick-loading" Linux apps some laptop manufacturers are including so people can check their email, etc.) accessing the network is one of the main purposes for turning on the machine in the first place. It would royally piss people off to have a quick loading screen, log in and then see "Hold up, still starting up the network". (Just as frustrating as starting a Windows or Mac, getting to the desktop and still waiting while services and programs are loaded).

      Come to think of it, what people really need to do is take a good look at modern OSes and determine EXACTLY what still needs to be there and what's cruft. Some of the daemons/services we're launching made sense 15-20 years ago. Does the fax daemon really need to start on my Mac? Does the Group Policy Client need to be started on my Vista box when I'm not on a domain? There's lots of stuff that at one point probably made sense to someone but now is just extraneous.

      • by sofar (317980) on Thursday October 02, 2008 @04:05PM (#25238603) Homepage

        actually we do bring up the network daemon (either connmand or network manager) as soon as we can, but we don't stop the entire startup process.

        on my test system here it runs dhclient about when X starts up and the network card receives a reply with a few seconds from that, long before I can start firefox :)

      • by schwaang (667808) on Thursday October 02, 2008 @04:09PM (#25238659)

        Sendmail's main purpose in the typical Linux desktop configuration (say, Fedora) is delivering logwatch output to root. [Logwatch attempts to distill the important stuff from system log files.]

        But sendmail can be started lazily (in the background) so as not to slow the boot. Or sendmail can be replaced with a lighter weight smtp daemon. Truly though, logwatch-by-email should die for non-enterprise desktops. It's so 1980s it just hurts.

        IMHO logwatch should be replaced by some kind of graphical notification widget which requires authentication to actually view the details, since they can be sensitive. As it is, I haven't read my logwatch emails in months, but if SMART is complaining about an immanent disk failure I'd *really* like to know.

        • Re: (Score:3, Funny)

          by the_womble (580291)

          if SMART is complaining about an immanent disk failure I'd *really* like to know.

          An immanent [askoxford.com] disk? Computers really are getting everywhere.

        • by jd (1658) <<moc.oohay> <ta> <kapimi>> on Thursday October 02, 2008 @05:16PM (#25239509) Homepage Journal

          Yeah, but you don't need a full ESMTP server for that - a wrapper for the local delivery agent that speaks classic SMTP (but ignores most of it) should be sufficient. In fact, if you're only using it to deliver to root, you've a choice of a tiny bit of text formatting, putting into a huge block of text and whapping it onto the end of root's mailbox, or doing a tiny bit of other text formatting and use the local mail delivery agent to do all of the work.

          If you've only one login account (the rest are for daemons or accessed via sudo), then the login code is excessively heavy. There's effectively only one user and effectively only one password. Those need to be in a password/shadow file for compatibility with other apps, but for machines that are essentially single-user, where the data is essentially fixed-length, you don't need search algorithms, routines to scan for the correct column, etc. You store two fixed-length blocks of data and then do a string compare and a byte compare. No files to open, no multi-layer authentication modules, etc. For a straight single-user desktop, you don't need such weight for a console login. You do for servers and other remote activity, but not for the console.

          XDM/GDM/KDM could be rigged to work under GGI or XGGI. They don't need the full X system. You can complete booting that whilst the user logs in.

      • Re: (Score:3, Informative)

        by grasshoppa (657393)

        You still get group policies assigned, whether you are in a domain or not.

        So yes. You need the group policy service.

      • by es330td (964170) on Thursday October 02, 2008 @04:48PM (#25239197)
        What really needs to happen is for there to be an informative display of what is happening when the system is loading, something that is one of my favorite things about linux. Most people wouldn't gripe about how long it takes for their system to load if they knew what it was that was loading. Sadly, I have stopped being amazed by the people who complain that "Windows loads slow" and then go in and find that they are incapable of saying "No" to any application that wants to install itself on their system. If you want the iTunes Helper and 6 different IE toolbars to load then you accept that requires time. If your fancy all-in-one fax/printer/scanner/roaster has some special monitor that has to load, suck it up and accept a slow load but at least allow the user of any OS to see what exactly it is that is getting put in memory when their system starts up.
      • Re: (Score:3, Insightful)

        But "The 'done booting' time did not include bringing up the network"? Um, ok... no.

        Consider that "bringing up the network" generally involves communicating with at least one other device. You can't really call it a metric of OS boot time when merely plugging into a different network (or none at all) might change the result.

        Come to think of it, what people really need to do is take a good look at modern OSes and determine EXACTLY what still needs to be there and what's cruft.

        I would much prefer simply cutting them out of the boot process, or making a smarter boot process.

        For example: Maybe I do want a MySQL server running. But I certainly don't want you to delay my login screen while I wait for it to start. I probably don't want it eating u

      • by drew (2081)

        It would royally piss people off to have a quick loading screen, log in and then see "Hold up, still starting up the network". (Just as frustrating as starting a Windows or Mac, getting to the desktop and still waiting while services and programs are loaded).

        They wouldn't be the first, unfortunately. The Intel wireless driver on my Dell Inspiron laptop works that way. Somehow they've completely disabled all of Window's built in network configuration and replaced it with a tray app that starts as part of t

    • by not already in use (972294) on Thursday October 02, 2008 @03:46PM (#25238359)

      but if this can be applied generically to most distributions then it should present an excellent opportunity for advertisement.

      Not going to happen. If you read the article, you'll see that they compiled all drivers directly into the kernel, so it is essentially an embedded device now. Also consider the fact that they are using a SSD, which is going to decrease boot times regardless of any boot-process improvements.

      So basically, you could never apply these speed increases to a generic distro.

      • by nschubach (922175) on Thursday October 02, 2008 @03:54PM (#25238451) Journal

        ... but an OEM can. (If they were so inclined.)

      • by Cyberax (705495)

        So? I used to run all-static kernels for 10 years, until I got tired of compiling my own kernels and switched to distro-provided kernels.

        The article says that you can compile-in drivers for about 95% of commonly used devices and put the rest of them on small initrd.

        Without SSD you can get abot 10 seconds for boot. Proably less, considering that you can optimize file layout and read everything in one big request.

      • Re: (Score:3, Interesting)

        by Anonymous Coward

        Is there any good reason the kernel can't be compiled with device drivers automatically upon installation? Even if drivers change, it can ignore the compiled one in favor of a module, and/or have a "recompile kernel for currently installed devices" button.

        I also doubt the SSD is that big of an issue Windows already offers the option of using Flash ram sticks in the same way, and loading boot data sequentially on the fastest portion of the disk is also a viable (and popular) way to boost speeds.

        Step 1 is m

        • by PReDiToR (687141) on Thursday October 02, 2008 @05:46PM (#25239919) Homepage Journal
          I picture something like that, but further.

          Once the distro installer has finished it would attempt to boot the system to the graphical login. If the login screen came up it would save the state of the machine to a fast loading RAM image that GRUB could directly inject to RAM.
          Reading ~100MB of system should take seconds on any machine, and the code area taken up by the GRUB routine could be overwritten with a memory offset command embedded in the first few bytes of the image.
          Once the image is in RAM the execution starts up again immediately waiting for your login details.

          Of course, hardware would have to be hashed to make sure that the image was still compatible with the machine and that the disk hadn't been moved to a different one. Upgrading the hardware or the kernel, software updates et cetera would require the image to be resaved, but those are easily achieved.
          Taking into account the size of the image, I guess that someone could code the installer to compile the kernel with the modules the system uses built in. Maybe as a function of the exit procedure. "Optimise load time - warning! This will take quite some time"

          Basically I guess what I'm saying is something like a hibernate file, but one that is rarely changed and only contains the system, not the applications running in a session.
          • Re: (Score:3, Insightful)

            by sofar (317980)

            we already boot in seconds. the totaly size of the data read from disk at boot is UNDER 100mb total on our 5-second boot systems.

            you don't provide a solution to speeding things up, only an alternative that works in limited cases. reinventing hibernate at best.

      • I'm running a few Ubuntu boxes and I just "apt-get install powertop" and fired it up.

        It found a few items on one of the older boxes and one item on the newer boxes.

        So I followed the simple directions "press U to enable USB sleep" or something like that and now the app says that my boxes are waking from idle 5 times a second.

        Whether that is good or not ... I have not noticed any increase in performance. But it seems to be applicable to my generic Ubuntu systems.

      • by sofar (317980) on Thursday October 02, 2008 @03:58PM (#25238497) Homepage

        says who?

        We talked with both the fedora and ubuntu developers at the LPC and even they agreed that a LOT more drivers should be compiled into the kernel instead of being modules (c'mon, ext3 as a module? really?).

        99% of what we did to make this work in 5 seconds applies straight for generic laptops and even most people's desktop sytems.

        The speedups _still_ are relevant with generic spinning media too. Maybe those are not as fast as SSD's, but the principle is still the same (IOW, for instance reading data in the order that you need it, is better than reading it in the order that it is scattered across the hard disk)

        speeding up the kernel to boot in 1 second is TOTALLY applicable to generic distros (not only that, it's relatively easy and we basically already did that).

        speeding up X startup to be 1.5s is TOTALLY applicable to generic distros.

      • by MMC Monster (602931) on Thursday October 02, 2008 @04:02PM (#25238569)

        Why not?

        How about the first time the system boots, it profiles what drivers are installed. It then recompiles the kernel to include those drivers.

        On subsequent reboots, it uses the recompiled kernel and then, once the system is up and running, check to see if something that is compiled in is no longer needed, and see if something has been added that should be compiled in.

        I'm sure it's not *that* easy, but maybe an idea for the future?

      • by ColaMan (37550) on Thursday October 02, 2008 @04:07PM (#25238639) Homepage Journal

        So basically, you could never apply these speed increases to a generic distro.

        Oh come now! Never say never!
        You could:

        - Boot with modular kernel.
        - Probe devices and get a list of loaded modules.
        - Recompile kernel with said modules built-in.
        - Boot with that kernel from now on.

        It's relatively scriptable - in fact, I think there's a "probe loaded modules and generate new .config" script already about the place. If the user is unwilling to wait for a kernel recompile during install, just stick with the modular kernel and incrementally compile during idle time.

        It's trivial. I'd code it up myself, but I'm a little busy at the moment, you understand.

  • Does it matter? (Score:4, Insightful)

    by suso (153703) * on Thursday October 02, 2008 @03:19PM (#25237923) Homepage Journal

    I see a lot of comments on the LWN article of people talking about starting services after the user sees the desktop as cheating. However, I ask, does this really all matter. I'm not sure how everyone else uses their computer but I only need to boot my Linux machine about once every 30-60 days. I don't need to dual boot like I did back in say 2002 and comparitively, the amount of time it takes for Linux and X to start up are practically irrelivent. I can imagine laptop users may feel much differently about this, but I thought that was the point of being able to suspend/hibernate.

    One thing that worries me is that a focus on ensuring a quick boot at the expense of a potentially less stable system is not a good thing. Fortunately however quick booting is not something that Linux requires, its something that distributions can decide to do or not, which is one of the strengths of the open source/Linux way.

    • Re:Does it matter? (Score:4, Informative)

      by Anonymous Coward on Thursday October 02, 2008 @03:23PM (#25237987)

      Yes.

        • by dfm3 (830843)

          Okay, so I kid. But when your have to wait every morning for your bogged-down workstation to load all sorts of services and client side junk that IT installs on their XP boxes, you get tired of it very quickly. The system is so sluggish and unresponsive for 3-4 minutes after login that I can usually brew a cup of coffee before clicking on the start button actually has any effect. That's 3-4 minutes during which I could be reading Slashdot, er, I mean doing something productive.

          There is absolutely no reason

    • by pwnies (1034518) * <j@jjcm.org> on Thursday October 02, 2008 @03:25PM (#25238015) Homepage Journal

      I'm not sure how everyone else uses their computer but I only need to boot my Linux machine about once every 30-60 days.

      Some people like to power down their computers to stop them from wasting energy at night.
      How they sleep without the sweet, sweet sound of fans running though leaves me dumbstruck.

      • Re: (Score:3, Informative)

        by kailoran (887304)
        Perhaps surprisingly, for some people suspend/hibernation actually works on linux so you can boot rarely while not keeping the machine on 24/7.


        I'm one of the less lucky ones that only have half of hibernation working, the "resume" part fails.
        • by not already in use (972294) on Thursday October 02, 2008 @03:49PM (#25238381)
          How ironic, with all the Vista bashing that tends to go on in threads like these. Vista boots relatively quickly, and hasn't been powered down for me for weeks since suspend/wake works perfectly.

          But at least someone, somewhere can boot linux in 5 seconds.
          • Re: (Score:3, Insightful)

            by gollito (980620)

            How ironic, with all the Vista bashing that tends to go on in threads like these. Vista boots relatively quickly, and hasn't been powered down for me for weeks since suspend/wake works perfectly. But at least someone, somewhere can boot linux in 5 seconds.

            Agreed. The only time I reboot my laptop is after updates/new software install. IMO the power management in Vista is the best I've seen.

          • Re: (Score:3, Insightful)

            by jonbryce (703250)

            If you ever end up with an uptime of more than 5 weeks in Vista, you should worry. It means you haven't installed the latest patches.

    • Re:Does it matter? (Score:5, Insightful)

      by arth1 (260657) on Thursday October 02, 2008 @03:36PM (#25238189) Homepage Journal

      Being able to boot in NN seconds isn't so impressive when you look at the incompatibilities it creates.

      On my networks, the servers connect to the DHCP server and get not only an IP back, but also the name of NIS servers, who in turn returns (among other things) autofs maps which are used to mount the home directories as well as providing login authentication. The xdm login window returns a list of currently available X servers.
      In other words, there are reasons why things run in the order they run, and any deviation will cause things to stop working.

      Improving things are fine, but not when it's at the expense of current and well-known functionality.

      • Re: (Score:3, Insightful)

        by chromatic (9471)

        On my networks...

        ... you can't take advantage of all of these improvements. Why penalize everyone who doesn't use NIS and autofs?

      • Re:Does it matter? (Score:5, Insightful)

        by tepples (727027) <tepples@[ ]il.com ['gma' in gap]> on Thursday October 02, 2008 @03:54PM (#25238455) Homepage Journal

        On my networks, the servers connect to the DHCP server and get not only an IP back, but also the name of NIS servers, who in turn returns (among other things) autofs maps which are used to mount the home directories as well as providing login authentication.

        What you describe is similar to what Windows calls "domain authentication". Not every computer logs on to a domain, especially in the home or home office environment where a fast boot is paramount.

        The xdm login window returns a list of currently available X servers.

        Then have it refresh the list whenever a network interface comes up.

      • Re:Does it matter? (Score:4, Insightful)

        by sofar (317980) on Thursday October 02, 2008 @04:01PM (#25238539) Homepage

        so you are saying that you would rather stare at a hung boot in text mode instead of having the possibility of working in offline mode in X?

        that does not make sense at all :)

        for network-client setups like you describe, we should still start X immediately and if the network fails or is slow, at least provide some interaction with the system (work offline, nudge network with login attempt etc).

      • Huh? (Score:3, Informative)

        by Sits (117492)

        I've administrated network authenticated openSUSE machines and they definitely benefited from booting faster (compared to older versions of openSUSE) - after all the sooner the kernel finishes the sooner you can start waiting for that DHCP lease...The key is that the moment someone says they want to run NIS/LDAP/NFS you just say "start everything that doesn't depend on the network while you wait for the network to come up". In your case NIS/NFS/autofs/xdm DO need the network so they have to wait until that

    • by mcgrew (92797) *

      If you're talking about a server I agree, but for a desktop, well, do you leave any lights on at your house 24/7? I don't. Electricity isn't free, and I don't like contributing to global warming any more than I have to.

      TFA showed no indication of the system being less stable. With a machine that boots virtually instantly, why would you NOT shut it off when you're not using it? IMO wastefulness is shameful. You should stop!

      Funny, it's usually us geezers who are portrayed in being stuck in your ways. I look f

    • I don't need to dual boot like I did back in say 2002 and comparitively, the amount of time it takes for Linux and X to start up are practically irrelivent. I can imagine laptop users may feel much differently about this, but I thought that was the point of being able to suspend/hibernate.

      Unless you end up stuck with a machine whose suspend/hibernate sequence is defective. On various computers running various operating systems, I've had no video, or no audio, or no network, or no mouse after coming out of sleep.

    • Re: (Score:2, Informative)

      I see a lot of comments on the LWN article of people talking about starting services after the user sees the desktop as cheating.

      Funny, but that's exactly how XP and Vista achieve their 'fast' boot times. XP doesn't actually boot much faster than 2000, once you realize that the services are all still loading in the background.

      But, yes, it does matter, laptop or not. Most desktop users don't leave their machines on 24x7. Just because you and I do doesn't, at all, mean that is typical usage.

    • by mikael (484)

      Seems like there is market for a fast-boot Linux distro which just install DHCP, network services, an X-server and an E-mail daemon/web browser to read E-mail. Perhaps you could call a thin-client Linux.

    • by drxenos (573895)
      It was the presenter that stated this, not the comments. It was something they didn't allow in their 5 second boot up. The comments were just, well, commenting on this.
    • Re:Does it matter? (Score:4, Informative)

      by elmartinos (228710) on Thursday October 02, 2008 @04:24PM (#25238853) Homepage

      Linux has always tried to be an excellent choice for a very broad range of uses. Just because you do not need fast boots does not nobody else does.

  • I'd love to see linux in general have better boot times. My install of ubuntu on my PC takes about 2.5 minutes while XP is up and running in about 1.5. On my laptop it's the reverse (windows taking forever, opensuse being relatively quick). As far as 'cheating' by loading services at the login screen, GO FOR IT! It's not cheating if it's making things better for the user, it's called being more efficient.
    • by X0563511 (793323)

      Personally I don't care for boot times as long as they are not huge. As a matter of fact, my system halts mid-boot awaiting a passphrase to access the rest of the drive.

      Stability is more important to me. Why does a 10 minute boot matter if I have to reboot once in two weeks, and that only because I need to unplug the box to clean?

  • At least the boot speedup. Slashdot-ed already.
  • TFA (Score:5, Interesting)

    by mcgrew (92797) * on Thursday October 02, 2008 @03:31PM (#25238115) Homepage Journal

    And no cheating. "Done booting means CPU and disk idle," Arjan said. No fair putting up the desktop while still starting services behind the scenes. (An audience member pointed out that Microsoft does this.) The "done booting" time did not include bringing up the network, but did include starting NetworkManager.

    It seems to me that the five seconds could concievably be brought down to virtually zero with cheating! My work PC slows down so much sometimes from antivirus, inventory controls, etc that it takes longer than that to add a record or open a table in an Access database. With a keyboard buffer you could stick a fake desktop and login in, and have the real desktop and login take over before the user finished typing in his password.

    • Re: (Score:3, Funny)

      by Dan667 (564390)
      Your problem may be using Access as a database. Ouch.
      • by mcgrew (92797) *

        I agree, I absolutely HATE Access. I rather liked dBase, didn't have any problem at all with Foxpro, and absolutely loved NOMAD. But as to NOMAN, I'm not sure they even have a mainframe any more. I wonder of there's a PC NOMAD?

        At least I'm not forced to use a spreadsheet as a database.

        • Re: (Score:3, Funny)

          by Johnno74 (252399)

          Access is a steaming turd that should be taken out back for a bullet in the head.

          I cannot express in words how much I hate access. I work/develop with microsoft tech all day, and I don't mind most of it, but access is a big bowl of shit.

          calling it a "spreadsheet used as a database" offends me. spreadsheets aren't that bad.

          IMHO, microsoft makes some pretty good stuff. Parts of vista are pretty good, .Net is very good, SQL Server is very good.
          Unfortunately for them their reputation is then tarnished by com

    • Re:TFA (Score:5, Interesting)

      by Shikaku (1129753) on Thursday October 02, 2008 @03:45PM (#25238327)

      Yes, please. More common users would benefit from this greatly. I would love a prompt for user and password while it is booting, because most users do not leave their computer all day, especially laptop and handheld/UMPC users.

      With desktop computers, I really think that the time it takes to boot into Ubuntu, THEN going into a Gnome prompt, THEN loading the services and desktop is a silly idea.

  • by mikael (484) on Thursday October 02, 2008 @03:32PM (#25238129)

    My stepfather still has an old Pentium III laptop with Windows 95 running on it. Booting the laptop to read an E-mail takes around 20 minutes. His advice to anyone who wants to use it, "switch on the PC, do something else like have a bath, do the lawn, read the newspaper, or have a coffee, and the PC will be ready to use before you know it".

    • Looks like someone needs DSL [wikipedia.org], DSL-N, or Puppy [wikipedia.org].

    • Re: (Score:2, Insightful)

      by baka_toroi (1194359)
      Man, WTF? I used to use Windows 95 on a 486 with 16 MB and it didn't take nearly as much as that. It should be blazing fast on a Pentium III.
    • I find that if a PC is dragging its feet it's either a memory or harddrive problem. I was doing some development on a 1.7Ghz system with a really old 40GB drive and it took forever to get the program loaded. I popped in a brand new harddrive and the program loads in a few seconds. The problem was largely getting information from the disk.

      If you decide to just get rid of the laptop, get an external enclosure and use the drive as a backup drive for any other system.

      If you've got less than 128MB of ram you

    • Re: (Score:3, Informative)

      by BUL2294 (1081735)
      I call bullshit--unless he's doing some serious work for spyware companies and sending e-mails peddling "Vla*g-ra" -and/or- has a serious hard drive or memory problem. Let's see, Win95 required a 386DX with 4MB RAM--although that setup was painfully slow. Win95 recommended a 486 with 8MB RAM. So, unless you are running a lot of startup apps, Win95 (including Win95B) should boot with 8MB RAM and have a WIN386.SWP of 0 bytes. So, even if he has a PIII/450 with 64MB RAM (even then most laptops came with 128MB
  • by pwnies (1034518) * <j@jjcm.org> on Thursday October 02, 2008 @03:38PM (#25238217) Homepage Journal
    ...here's the text from the oreilly article:

    O'Reilly News recently interviewed Arjan van de Ven [fenrus.org] about his efforts to improve Linux performance and reduce power consumption. Arjan works for Intel in the Open Source Technology Center [intel.com]. This interview is approximately 30 minutes.

    One of the projects you're probably most known for in the past couple of years is the PowerTOP [lesswatts.org] utility, which I found very fascinating. Looking at some of the gains you've made over the past 18 months, it seems like Linux-based devices are saving a lot more power than they used to. What do you consider the big successes in the past year and a half?

    To be honest we fixed effectively the entire Linux desktop space. It's not--PowerTOP is more--it's not just what we fixed with PowerTOP is not individual pieces. We fixed everything. For me that was a success.

    Is that everything in terms of not just desktop but servers as well?

    Yeah; we fixed not just Evolution. We fixed Firefox; the thing with Firefox was that it wasn't one thing that was broken. Everything had problems and we had to fix all of it. So for me the success was how quickly everything got fixed; it was just amazing.

    In this context you consider fixed--everything is no longer broken in the same way or--?

    Everything is no longer keeping the CPU out of idle basically.

    Do you have a reference machine? I guess I'm asking what's your benchmark for this, a particular software configuration stack or particular type of machine, or are you willing to say it's pretty much every Linux based machine out there?

    I'm looking at several machines--my own laptop but to be honest, what runs on my own laptop is what I care about most. At least that's where I got more battery life, this is where I see the changes. I tend to run a quite rich environment on my laptop but I also look at service. We look at all kinds of machines and we see the same trend everywhere in that all the various pieces of it--never polling or keeping the CPU up. They all got fixed.

    In fixing this, is there a component of education, for example, saying "Instead of doing a busy wait on a select loop or continually polling you should set a kernel timer and wait for that to call you"?

    That's part of it but the biggest thing is that you had no visibility. Just two days ago at IDF I spoke with a developer of the GNOME desktop and he said, yeah; when I saw it happen I fixed it in 10 minutes, but you don't know it's there until you see it from PowerTOP. Adding the visibility turns out to be enough for people to start fixing it. They know how to fix--how to not poll most of the time.

    You can't fix something you can't measure.

    If you don't see that it happens you don't know it happens and you can't fix it.

    Are you getting the same sort of results from other projects you run into?

    GNOME was there but it's almost everybody goes oh yeah; we should have not done that; either they fix it themselves or some--a lot of people give them the fix and in general it's like oh yeah; we shouldn't have done that. Unless you see what's happening you don't know what to fix, so the biggest thing that PowerTOP did was add visibility. We can see under the hood what's going on and then we can fix it. And quite often the fix is very simple.

    It sounds then, maybe I should be able to say that just about everybody is happy to see this. Is that the case?

    Yes; people--all the developers I've worked with--and that's quite a few--they all go oh yeah. Thank you for the fix; we should have no problems in the first place. We didn't know this; it's fixed now. In the beginning I did most of the fixing when PowerTOP was very new and now days the people do it themselves. The developers learn

  • by Sits (117492) on Thursday October 02, 2008 @03:38PM (#25238219) Homepage Journal

    This is effectively related to an earlier Slashdot story about the changes Mandriva are making to speed up boot on their distro [slashdot.org]

    In an attempt to head off the inevitable here's a link straight to the existing
    Interesting but how useful, really? thread (Yes! No! I have a Mac! I use suspend! I use hibernate! Suspend is broken for me! Hibernate is broken for me! Hibernate takes too long with 500Mbytes! Why do Linux people always say change your habits? Etc.)

    What I really want to know is what can be done about usb-storage and pciehp (PCI Express hotplug). I have an EeePC 900 using a kernel with Arjan's fastboot patches [lkml.org] and with USB entirely disabled and pciehp turned off the kernel mounts the root filesystem in just over one second. With USB on and pciehp in use it's over 5 seconds....

    Finally here's a link to Arjan's slides from the presentation about 5 second boot in PowerPoint format [fenrus.org] and a YouTube video of the 5 second boot on an EeePC 901 [youtube.com].

  • by russotto (537200) on Thursday October 02, 2008 @03:39PM (#25238229) Journal

    I'd love for my MythTV box to boot faster. Since it's not silent (though the TV fans are louder, the TV isn't always on either), I leave it turned off, and the long boot time makes it less appliance-like.

  • rooted in 10.

    Speed is great and all, but is it secure?
  • by techno-vampire (666512) on Thursday October 02, 2008 @04:03PM (#25238575) Homepage
    Note that nowhere in the article is there any mention of the processor, its speed or the number of cores. There's also not one word about how much RAM the machine has. With enough RAM, you can load your entire system into a RAMdisk and even if you don't have SSM access time becomes (effectively) zero. Also, of course, a 2Ghz quad core machine is going to boot faster than a 1 Ghz single core. I'm not saying they're cheating or anything, but these specs are something you need in order to evaluate what they've done, and they're not telling us.
  • by Geheimagent (679949) on Thursday October 02, 2008 @05:45PM (#25239907)
    I suspend or hibernate most of the time. I reboot my laptop only when the kernel gets a security fix. I don't care if that takes 40 seconds.
  • Compilers Suck (Score:4, Interesting)

    by logicnazi (169418) <logicnazi@gREDHATmail.com minus distro> on Thursday October 02, 2008 @09:32PM (#25241703) Homepage

    The real lesson from all this load time buisness is that our compilers still really really suck. I mean the truth is that when you boot your computer there is only a tiny bit of logic that really needs to go on because only a small amount of stuff changes between any two boots (and less between a boot and a power off).

    A truly well desgined system wouldn't care about arbitrary boundaries between this program and that one, it would hunt down optimization opportunities everywhere and automatically reduce boot up to an extremely lean and quick procedure without adopting the harms of merely loading an old image.

    I mean to take one example a substantial amount of time during start up is probably spent searching for and then parsing configuration files. So long as their is no cross cutting OS level JIT compiler that can deal with both system IO code and application code there isn't much we can do about this without massive investment of effort. However, in principle there is no reason that the system couldn't simply read the preparsed data from a cache and jump directly to the real substantive logic that needs to be done on boot (checking out network conditions, looking for changed hardware, dealing with changed configs)

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