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Torvalds Explains Scheduler Decision

kdawson posted more than 7 years ago | from the it's-the-guy-not-the-code dept.

Linux 411

Firedog writes "There's been a lot of recent debate over why Linus Torvalds chose the new CFS process scheduler written by Ingo Molnar over the SD process scheduler written by Con Kolivas, ranging from discussing the quality of the code to favoritism and outright conspiracy theories. KernelTrap is now reporting Linus Torvalds' official stance as to why he chose the code that he did. 'People who think SD was "perfect" were simply ignoring reality,' Linus is quoted as saying. He goes on to explain that he selected the Completely Fair Scheduler because it had a maintainer who has proven himself willing and able to address problems as they are discovered. In the end, the relevance to normal Linux users is twofold: one is the question as to whether or not the Linux development model is working, and the other is the question as to whether the recently released 2.6.23 kernel will deliver an improved desktop experience."

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Nerds (-1, Troll)

Eightyford (893696) | more than 7 years ago | (#20025349)

I know this is news for nerds, but I'm just curious as to how many people here actually have a clue as to what this article is about.

Re:Nerds (5, Funny)

kcbanner (929309) | more than 7 years ago | (#20025377)

Everyone except you.

Re:Nerds (0, Troll)

Neotrantor (597070) | more than 7 years ago | (#20025419)

hey buddy, go fuck yourself.

Re:Nerds (-1)

Broken scope (973885) | more than 7 years ago | (#20025469)

Anyone with a vague Idea of how an OS works?

Re:Nerds (3, Funny)

Anonymous Coward | more than 7 years ago | (#20025509)

Actually, I have no idea how an OS works and even _I_ know what this article is about.

Re:Nerds (1)

Yetihehe (971185) | more than 7 years ago | (#20025519)

It's about Completely fair scheduler and staircase-deadline cpu scheduler and problems with their developers. If you don't know what a cpu scheduler is, you are not slashdot's target audience, "Tere is nothing for you to see here, please move along".

Re:Nerds (3, Funny)

larry bagina (561269) | more than 7 years ago | (#20025597)

If you don't know what a cpu scheduler is, you are not slashdot's target audience

Look at the front page much?

Re:Nerds (1)

networkBoy (774728) | more than 7 years ago | (#20026381)

Yes, but he has it filtered to only "Linux Flamewars"

Re:Nerds (5, Insightful)

Tadrith (557354) | more than 7 years ago | (#20025837)

That's not really fair. Slashdot pretty much covers all things science, be it computer science, or quantum physics. There are frequently articles posted which I, being in the field of computer science, do not necessarily understand or comprehend. I'm not going to tell all of the quantum physicists out there that "slashdot is not the place for them" because Slashdot IS for them. While it might have a technical slant to it, I think it's a place for anyone more interested in hearing news of advancements in various scientific fields, rather than what prison Paris Hilton is going to next.

For that matter, even when I don't understand what an article is talking about, I am still usually more than interested to read about it.

Re:Nerds (-1, Troll)

MrHanky (141717) | more than 7 years ago | (#20026257)

That's just pure and utter drivel. Slashdot isn't and has never been a science site, unless your definition of science is 'what concerns science fiction' (i.e. stuff with computers, gadgets and robots).

Re:Nerds (1)

pimpimpim (811140) | more than 7 years ago | (#20026149)

If all people would react as parent did here, I would indeed not think of myself as slashdot audience. However, luckily there are a bunch of slashdot users that understand that slashdot has a mix of topics, and a mixed audience. Someone that knows about the topic at hand and is not too short-sighted to explain to the interested readers that are not acquainted to the current topic what it is about, that seems to me slashdot's target audience. The main reason why I come here is that I tend to learn new stuff from some of the more insightful comments, not because I already know everything of cpu schedulers so I can bash other users without having to explain it to them.

Re:Nerds (1, Informative)

Anonymous Coward | more than 7 years ago | (#20025799)

Oh, I'm sorry. Please go under your preferences and change them to show apple stories only.

Re:Nerds (1, Funny)

hughperkins (705005) | more than 7 years ago | (#20026157)

The scheduler is reponsible for deciding which programs can use the processor when. So, lets says you're running Word (not likely on linux, for quickest example I could come up with), and Word is for some reason using 100% cpu. Well, depending on how the scheduler works, that is how the cpu is shared between processes, other applications might continue working ok, or might freeze up entirely whilst they wait for Word to finish.

So, the scheduler controls how well different applications work together at the same time.

Torvalds jumps shark - Film @ 11 (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#20025359)

Oh Yeah Fr15t p05t!

Re:Torvalds jumps shark - Film @ 11 (1, Funny)

Anonymous Coward | more than 7 years ago | (#20026229)

Well, your scheduler certainly wasn't fair on that one.

good for you (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#20025403)

nobody cares about the scheduler. I do care about the lack of ZFS support. Get over your "not invented here" syndrome and integrate it already.

Re:good for you (2, Interesting)

RebelWebmaster (628941) | more than 7 years ago | (#20025421)

Hasn't Linus already said he's very interested in adding it into the Linux kernel (going so far as to say that it could be a reason to consider going GPLv3 in the future if Sun releases Solaris under it), but right now it's tied up in closed source?

Re:good for you (4, Informative)

larry bagina (561269) | more than 7 years ago | (#20025499)

It's not closed source. It's available as part of OpenSolaris (CDDL). FreeBSD didn't have a problem integrating it.

Re:good for you (2, Interesting)

RebelWebmaster (628941) | more than 7 years ago | (#20025593)

Is CDDL compatible with GPLv2? I may have mispoke in my first post, but I think the gist of what I was trying to say is still there. ZFS is behind a license which isn't compatible with the license Linux is under. Or am I completely misunderstanding things? I'll admit I'm far from an expert on these matters...

Re:good for you (1)

TheRaven64 (641858) | more than 7 years ago | (#20026225)

The CDDL is non-viral, so FreeBSD could integrate it without affecting the license of anything else. If you don't use ZFS, the fact it's in the kernel has no impact on you. The CDDL has a patent-defence clause and some attribution requirements which makes it incompatible with the GPL, however, so code can't be shared between GPL and CDDL projects, even if they are in separate modules. Since Linux is released under the GPL, every module must be under GPL compatible licenses, irrespective of whether they contain, or depend on, any GPL'd code.

I don't know how well FreeBSD's ZFS port works (I'm using UFS2), but proper support for ZFS requires radically re-thinking your layering, and moving away from the traditional block-device, filesystem, VFS layers.

Re:good for you (4, Informative)

QuoteMstr (55051) | more than 7 years ago | (#20026331)

Since Linux is released under the GPL, every module must be under GPL compatible licenses, irrespective of whether they contain, or depend on, any GPL'd code.

That's not true [] . Non-GPLed kernel modules are "tolerated" by the Linux kernel developers, and in principle, a ZFS module could be created and loaded with no problems, assuming it doesn't rely on GPL-only symbols. AFAIK, the VFS doesn't have many of those.

What can't happen under the CDDL is the ZFS code being included in the kernel source tree the same way XFS, ext3 and so on are. That doesn't mean you can't maintain and distribute a module separately! The only reason a ZFS module doesn't exist today is that nobody's gone through the trouble of creating one.

Re:good for you (5, Funny)

Anonymous Coward | more than 7 years ago | (#20025513)

I'm sorry but the flame wars over whether you call it zee eff ess vs. zed eff ess would make the vi vs. emacs flamewar look like a watergun fight. It would likely tear the Linux project apart as radical Zeddites suicide bomb the Zee Alliance.

Re:good for you (0)

Anonymous Coward | more than 7 years ago | (#20025531)

It's simply a matter of licensing incompatibility issues, ZFS is licensed under the CDDL, which cannot be readily incorporated into the linux kernel.

Re:good for you (2, Insightful)

whoever57 (658626) | more than 7 years ago | (#20025575)

nobody cares about the scheduler. I do care about the lack of ZFS support.
Get over your personal issues already. I was able to improve the performance of a file server by changing the I/O scheduler from the default. I care!

Its the desktop stupid! (5, Interesting)

bradbury (33372) | more than 7 years ago | (#20026067)

Have you improved it to the point that when the system is borderline out of main memory or has a moderately high load average it actually *works* as a desktop system?

E.g. when Firefox is consuming 65-70% of main memory and slower than #%#$ and you know it is waiting on swapped out pages and your swap rate is measured in the dozens to hundreds rather than hundreds to thousands (on vmstat)? (I mean really, how can one take an operating system seriously when only memory is at 100% and not CPU + memory + Disk I/O?)

The real issue, for those who have read comments that Con has made in interviews, seems to be the lack of concern on the part of most of the "in-crowd" Linux developers for performance on the desktop. In part this seems driven by the fact that the people who actually get paid to maintain Linux, benchmark it and "improve" it only care about its performance in server farms and *not* on the individual desktop. I will weigh in on the side of desktop user out there (that wants the Linux sitting beneath their desk to devote its every waking minute to making *them* happy) by saying that if my mplayer "hangs" in the middle of a song (only to continue with a loud burst of noise 10 seconds later) when the CPU is busy with "nice -19" processes, my Firefox browser takes half a minute to scroll a page or open a screen) when memory is tight, and it takes minutes to bring up a tab or minimized program I haven't touched in 3 days and return them to a functional state then the operating system *Has a PROBLEM*.

Con was very clear in his interviews that the problem is the lack of caring about *desktop* performance. Given my comments in the previous paragraph -- some of these areas may be very difficult to benchmark and as a result one is left with nothing but handwaving and loud voices when it comes to discussions about whether the problem exists and how it should be fixed.

I will say this, in the mid-'90s I used X-windows under Unixware on *Pentium 1s* as a desktop machine. I now use X-windows under Linux on a Pentium 4 (with 5-10x more main memory) as a desktop machine. I would argue that my desktop user experience is as problematic now as it was then *despite* the hardware improvements. That IMO is what Con felt was the problem he was trying to address. That is what it would appear the core Linux developers may be failing to address. Con's points raised my awareness level to the extent that I actually went investigating to see whether there were open source distributions of the BeOS and/or Darwin (which is based on Mach) available since they are based on different OS architecture models and might be more end-user friendly [1]. I was hoping to find something I could run in a VM under Linux on my current hardware without major file system surgery. But I have little confidence that such an approach would fix core problems with the Linux scheduling and paging systems. I would *love* to see a real side-by-side comparison of Linux vs. FreeBSD for desktop users with an emphasis on how BSD scheduling, paging and swapping may be different (better?).

(And as a side note, I could care *zero* about the performance of Linux in file server applications!)

1. I did use both Nextstep (on Pentiums) and IRIX (on a R4000) for a while and found both to provide better end-user experience than Unixware (X) or Windows (95-98). I am disappointed that Linux barely manages to match those experiences given the hardware available nearly a decade later.

Re:Its the desktop stupid! (5, Interesting)

TheRaven64 (641858) | more than 7 years ago | (#20026329)

I would *love* to see a real side-by-side comparison of Linux vs. FreeBSD for desktop users with an emphasis on how BSD scheduling, paging and swapping may be different
FreeBSD currently has two schedulers:
  • The old 4BSD scheduler has been tweaked a bit in the last decade, but is still fairly similar to the original. It is a high-throughput scheduler, which works well on servers and does okay on desktops.
  • The newer ULE[1] scheduler is latency-focussed. It prioritises I/O-bound tasks and respects 'nice,' so is generally much better for desktop use, where a little throughput can be sacrificed for responsiveness.
I've been using ULE since the 5.x series, and it seems nice. It's been improved a lot since originally being integrated. It's hard to make a good benchmark for this kind of thing, because what you are really trying to optimise for is 'user experience.' The Windows scheduler has a trick where it prioritises the process owning the foreground window, hoping that the user's attention is on that window, so they get a perceived boost in responsiveness. Doing this on *NIX would require window manager cooperation.

[1] ULE doesn't stand for anything, it was just chosen so the option in the kernel config file for adding it would be SCHED_ULE (SCHED_4BSD for the other one).

Linus as the benevolent dictator again (5, Insightful)

Anonymous Coward | more than 7 years ago | (#20025457)

As it seems many others don't agree to his opinions of Con, []

Re:Linus as the benevolent dictator again (3, Insightful)

Bin Naden (910327) | more than 7 years ago | (#20026107)

As Linus explained, he has tough decisions to make and the fact that CFS beat out SD this time, doesn't mean it will remain that way in future releases. Con should have sucked it up and worked harder on his scheduler.

Re:Linus as the benevolent dictator again (0, Insightful)

Anonymous Coward | more than 7 years ago | (#20026187)

Linus takes his position as "benevolent dictator" too seriously. Specifically, he seems to root out strong personalities who aren't directly beneath him in the feudal order. All ego is his, all political judgment is his, all technical judgment is his. If you don't subjugate yourself to Linus and receive his personal blessing, then you aren't allowed to wield any of these things, because they all flow from him.

Obligatory backwards comments (-1, Troll)

Anonymous Coward | more than 7 years ago | (#20025481)

Yeah, but does linux run it?

Re:Obligatory backwards comments (0)

Anonymous Coward | more than 7 years ago | (#20025529)

If you're thinking about the SD scheduler.. then no, not anymore, at least not officially.

For those of us who are not kernel hackers, (4, Interesting)

MoOsEb0y (2177) | more than 7 years ago | (#20025487)

What do CFS and SD stand for in this case? The summary and linked articles do not describe this.

Re:For those of us who are not kernel hackers, (5, Informative)

larry bagina (561269) | more than 7 years ago | (#20025517)

CFS = completely fair scheduler

SD = staircase deadline.

That probably didn't clarify anything :/

seeming to care is a big deal (4, Insightful)

acidrain (35064) | more than 7 years ago | (#20025491)

Having had my fair share disagreements with customers over technical issues, it just isn't worth trying to "win." The damage to your working relationships is still there even if you are shown to be 100% right. Try and help them address their problems as much as you possibly can, while trying to compromise as little as possible of the design. It's called diplomacy, and it's the difference between being given huge amounts of responsibility, and wanting to quit. You don't even have to agree with them, you just have to make them think you care.

Finally, it is common for programmers to try to avoid a subset of the problems in an area because it gives them the ability to write something "correct." Certainly a very satisfying experience for a programmer. However, that is exactly why it can be a bad idea to let a programmer rewrite a messy module. Very soon you can find the users of that module asking why a laundry list of things don't work anymore and an idealist developer trying to argue that they shouldn't... And it is exactly those idealists that like to rewrite working code. Not that major rewrites are bad, just that they have to be approached by someone mature enough to both expect a list of things they overlooked, and be willing to work with customers to resolve them.

Re:seeming to care is a big deal (5, Insightful)

Anonymous Coward | more than 7 years ago | (#20026377)

From the discussion it seems that Con Kolivas tried very hard to do what you're describing and ultimately had to tell off a single guy who kept harassing him after receiving much, much reasonable treatment and accomodation. Businesses do this all the time.

It also seems that Linus was tricked into torpedoing Con by people who gave him a very warped account of Con's actions. Either Linus got played and turned into a political tool of some anti-ck people, or he's making it appear that way to seem like an innocent victim. Linus evidently screwed up big-time here... but that should be expected from time to time.

ok, one step further then (4, Informative)

acidrain (35064) | more than 7 years ago | (#20026379)

Whether Con was aware of it, when he tried to integrate into mainline Ingo was his main customer. Specifically the person he was trying to deliver work to. And Con committed the cardinal sin of telling a customer that the customer was wrong about what he wanted. Even if Ingo were too coked up to operate a keyboard reliably and had it all wrong, trying that never seems to work.

Did Con gain anything by refusing to re-introduce the hack to get X working the way it had previously under load? Even if he'd just put in a #define that allowed it, and then spent the next year arguing to take it out, there wouldn't have been this breakdown.

Linus, Games are important! (1, Redundant)

12357bd (686909) | more than 7 years ago | (#20025503)

The only important points to me are:

1) Games are basic to linux desktops, we need linux games, so if Con scheduler was best on games, please, incorporate those changes.

2) EGO's are a pain in the ass, it seems that Con has been refused by Linus , because he didn't take the whole history into acount, too bad, that kind of things happend in any not trivial project management. Don't let EGO's rule the ball, that's the most basic point a manager (Linus) has to respect to keep people on the project.

Re:Linus, Games are important! (3, Insightful)

MBCook (132727) | more than 7 years ago | (#20025619)

Number one can't be done some times. You may want Linux on the desktop, but at this point it is big on the server. It is used for a LOT of important stuff. If a scheduler makes games better but hurts general server performance, they just can't put that in without people eithe forking or switching. Now if it improved games and other desktop usage quite a bit but had a tiny effect on servers, that could be tennable. But if the effect wasn'nt tiny, they just couldn't blindly merge it.

All that said Linus makes a good argument. If the guy wasn't addressing problems well and was just arguing "that's not my scheduler's fault" or "prove that's a big problem" etc instead of working with people, there is a very good reason not to merge the code. Ingo wrote his quick and has spent lots of time with people since he did that working with others to find and fix problem workloads. He just seems to have been much more responsible about maintaining his scheduler and it's good performace.

There are trade-offs in evertying, and it sounds like Linus made a perfectly valid one here.

Re:Linus, Games are important! (5, Informative)

irwiss (1122399) | more than 7 years ago | (#20025747)

"If a scheduler makes games better but hurts general server performance..."

IIRC that is the reason Con together with another person, whose name I can't
can't be bothered to look up, wanted to merge plugsched to which they got a
reply along the lines of "too much choice will split contributors" [] or some such

And then Ingo turns around on himself, and claims something along the lines of
"Oh okay, you should work on plugsched, may be it'll get merged" []

Re:Linus, Games are important! (1, Insightful)

Anonymous Coward | more than 7 years ago | (#20025779)

Like a guy can't be convinced of a good idea after some thought and debate?

Re:Linus, Games are important! (1)

Rakishi (759894) | more than 7 years ago | (#20025841)

IIRC that is the reason Con together with another person, whose name I can't
can't be bothered to look up, wanted to merge plugsched to which they got a
reply along the lines of "too much choice will split contributors" or some such
Well too much choice leads to bad things. Essentially each will be optimized for a subset of users despite the fact that they aren't in reality disjoint subsets of users. People run tons of things on their systems that don't fall into a single category, sometimes it's for testing and sometimes it's for actual use. Add in all the people who pick the wrong one and you have trouble. Remember that there are likely TONS of areas where such choices can be added in.

Re:Linus, Games are important! (1)

irwiss (1122399) | more than 7 years ago | (#20026047)

Well, there already /are/ different io schedulers, which you /can/ switch at runtime,
they don't seem to be causing any serious trouble.

I thought the whole philosophy of linux is that the OS doesn't assume the user is
braindead. People who might 'pick the wrong one' usually don't compile kernels and
use what their distro provided.

Besides, nobody said every scheduler out there will be merged into main tree,
Linus could limit it to fairly balanced and tested/reviewed/wanted schedulers, and keep
the special-case ones as separate patches which would not disturb anyone but the
people who are interested in those cases specifically.

To the poster above(#20025779): I'm not following lkml that closely, but I have my
doubts that there was any debate. If you have a link to post, please do so -
I'm enjoying all the drama around the issue... Geek soap opera anyone?

Re:Linus, Games are important! (2, Interesting)

miffo.swe (547642) | more than 7 years ago | (#20026095)

1. Games run just perfectly on Linux with often better speed than in Windows. Every single game i has played in Linux has worked perfectly and smoothly. What Linux needs for gaming is more normal users who buys games. If there is a market someone will fill it quickly. I will also strongly refute that games are essential to desktops. There are infact people who use their computer to actually do something useful. 2. This decision has nothing to do with egos. This guy just happens to believe that its essential to speed up the kernel when the only slow apps in Linux are non-native apps like Java, OpenOffice or Firefox. Those are not slow because of any sheduler but because they are written with slow toolchains. More work on making the kernel more responsive wont help at all at this stage.

Re:Linus, Games are important! (0)

Anonymous Coward | more than 7 years ago | (#20026479)

1) Games are basic to linux desktops, we need linux games, so if Con scheduler was best on games, please, incorporate those changes.
The vast majority of people don't play games on their PC. Games would be nice... but PC gamers are constantly overstating their significance. When it comes to a scheduler, there are a lot of considerations that take priority over the performance of games.

Linus wins by default (2, Insightful)

heinousjay (683506) | more than 7 years ago | (#20025545)

The guy walked away. It's like quitting the Internet. Obviously if your reaction is to take your ball and go home (and I know, the ball is everybody's in this situation, but go with it) then you aren't mature enough to handle the responsibility Linus requires.

Re:Linus wins by default (5, Insightful)

arivanov (12034) | more than 7 years ago | (#20025991)


If we look at the core linux developers every single one of them has been flamed into a crisp by Linus on the average every few years (and some of them flamed back in turn). Every single one of them has had something turned down in flames and an alternative merged as well (in some cases Linus admitting that he made the wrong choice later). And I cannot recall anyone of them behaving like such a hissy primadonna.

Similarly, I have flamed people in a crips at work, I have been flamed back and I still work with this people 8+ years later. In some cases we have even come again to the same company and the same team to work together. It is just software, it is just a job and any code you have ever written can and would be ripped out by the project leader one day to be replaced by something else. Accepting this as a given is a sign of maturity. If you cannot do that, you are not mature enough to maintain a critical part of a software project. You should go away and play with toys in the sandpit for a while until you grow up.

Sorry, the guy does not get a bit of my sympathy.

Hm... (0)

Anonymous Coward | more than 7 years ago | (#20025553)

This Linus character showcases how much we (nerds) lack tact. Either we better learn some, or grow super thick skins as pre-requisite.

Oh, this post? No tact? I'm an AC, asshole.

"desktop experience" (2, Interesting)

drDugan (219551) | more than 7 years ago | (#20025633)

which kernel scheduler is pretty low on the list of factors affecting what the Linux desktop experience is all about...

frankly, really high quality experiences take organizational planning and leveraging the expereince of huge groups in way that the "bazzaar" model of software developemnt in open source does not do well. Would someone please just build a mutual benefit corporation for open source users and maintainers? Let's start paying for project managers and the other experienced professionals required to make a "desktop experience" and you will see Linux take over.

well i don't know who did what, but ... (1)

schwaang (667808) | more than 7 years ago | (#20025885)

the Linux desktop responsiveness definitely improved (in my subjective experience) in the past two years or so.
If that was Con's scheduler, then thanks.

At this point I blame GNOME over the kernel for any remaining sluggishness, but then maybe my 1.2GHz athlon is just obso1ee7.

Re:"desktop experience" (1)

etnu (957152) | more than 7 years ago | (#20026449)

Do you have any idea what you're talking about? The "desktop experience" that you're referring to falls into the hands of organizations that actually make desktop environments, such as KDE or GNOME. Linux is the Kernel. It is one component of a large eco system that, taken together, make up an "operating system". Red Hat Enterprise Linux (RHEL) is an operating system. Ubuntu is an operating system. "Linux" is not, and never will be, an "operating system", and it certainly won't be a "desktop experience". If a commercial company wants to make a desktop environment for Linux, more power to them! Apple has already proven that building a desktop environment on top of a high quality open source kernel is an excellent strategy. Lastly, having actually worked at many major software vendors, the idea that "project managers" are what makes quality software is downright absurd. Project managers make sure that people are kept on task. You could argue that the OS community is in need of more designers and usability "experts", but in practice these people tend to be less clueful than engineers. Please try installing Ubuntu, then install Windows, and tell me which is a "better" experience. What prevents a popular OS desktop environment from emerging is simple: support. You need hardware support to make these things really survive. We're starting to see this happening with the Dell / Ubuntu partnership, but it's going to take a hell of a lot of work (and application support) before there's any real hope of competing with OSX, much less Windows.

recently released 2.6.23 kernel? (2, Informative)

loserMcloser (748327) | more than 7 years ago | (#20025637)

The official kernel site [] says 2.6.23 is only on release candidate 1.

Re:recently released 2.6.23 kernel? (0)

Anonymous Coward | more than 7 years ago | (#20026361)

So its like Windows XP SP1?

"the recently released 2.6.23 kernel" (0)

Anonymous Coward | more than 7 years ago | (#20025641)

Shouldn't that be "2.6.22(.1)"?

I find him rather rude (4, Interesting)

bogaboga (793279) | more than 7 years ago | (#20025663)

Having lurked on [] for several years, I find Linus to be rather rude. May be it's because English is not his first words are not well chosen. I must say though, that I excuse him because he produces, [or helps produce] a very useful product on the world today. That is the Linux kernel.

Re:I find him rather rude (0, Troll)

Soporific (595477) | more than 7 years ago | (#20025763)

Apparently the mods don't want you to say anything critical of Linus... Flamebait? Really?


Re:I find him rather rude (5, Informative)

Anonymous Coward | more than 7 years ago | (#20025855)

I think the apparent rudeness stems from something deeper than a mere incomplete mastery of english.

Linus is (as I am) a Finn by birth. No matter how long he has been abroad, he still follows Finnish habits and speech patterns at least to a degree. And they differ significantly from the west european tradition. For example, small talk is considered unnecessary or even rude in some situations. Getting to the point is a virtue in any conversation. To someone not familiar with this pattern, it will sound unfriendly! It's a two-way street: to me many english speakers sound terriby smarmy and guarded.

Of course, Linus is apparently also rather clever. The downside of cleverness is for many having little tolerance for fools, real or percieved.

An AFC (Anonymous Finnish Coward)

Re:I find him rather rude (0)

Anonymous Coward | more than 7 years ago | (#20026185)

I wonder if this is genetic... I'm third generation Finn-decent born in the U.S.A., and my whole extended family follows these habits and speech patterns.

An AFAC (Anonymous Finnish-American Coward)

Re:I find him rather rude (2, Funny)

rob1980 (941751) | more than 7 years ago | (#20026339)

Anybody want to claim themselves as an AFLAC (Anonymous Finnish Latin-American Coward)?

Re:I find him rather rude (1)

ConceptJunkie (24823) | more than 7 years ago | (#20026261)

Thanks for the cultural insight. I think I would tend to get along well with Finns. In fact, your description seems to fit well with a lot of non-Finnish, but smart, hardcore developers I have known.

Re:I find him rather rude (0)

Anonymous Coward | more than 7 years ago | (#20025861)

I think you speak from the heart, Torvalds. So I say to myself, this Lopez, your boss, he had chivatos like that working for him... his judgment stinks...

Re:I find him rather rude (1)

bdjacobson (1094909) | more than 7 years ago | (#20026007)

I'd say that's very likely.

I have that problem a lot. It's something along the lines that...I have to spend a whole lot of processing brain power on organizing my thoughts into sentences...seems to be my brain is a bit lacking in the "verbal" ability area. This coincides with reports of the same from other people who were born "purple", meaning that when they came out they were somewhat oxygen deficient. In babies whose brains are still developing, such oxygen deficiency appears to be permanentally harmful.

Anyhow, point being that I spend so much time trying to just say something half the time I've forgotten to think about _how_ I was saying it, and whether that was polite or the best way of saying it when talking with other people.

Re:I find him rather rude (5, Funny)

Just Some Guy (3352) | more than 7 years ago | (#20026175)

I must say though, that I excuse him because he produces, [or helps produce] a very useful product on the world today. That is the Linux kernel.

You're going to love this Theo guy, then.

I keed, I keed.

Re:I find him rather rude (1)

networkBoy (774728) | more than 7 years ago | (#20026319)

Took the words from my brain.

All in all though, I do provide some level of social leeway for these guys, in some way akin to my society's (sad) practice of forgiving DUI and DWS on Ms Hilton, failing to Lynch O.J. etc. when a person of lesser stature, say Mr. Peterson, gets the book thrown at him (rightly, but unequally). I suppose we grant our superstars leeway and since I see neither OJ or Paris as superstars I don't like the leeway. Then again, Hans crossed the line. There is no way I would excuse his (currently alleged) crime just because he wrote a killer FS.

Re:I find him rather rude (0)

Anonymous Coward | more than 7 years ago | (#20026421)

Then again, Hans crossed the line.
Nice prejudging without seeing the full evidence. I hope you never serve on a jury.

Re:I find him rather rude (1)

networkBoy (774728) | more than 7 years ago | (#20026469)

I suppose you don't read entire comments either, nice way of quoting for bias.

As the public information stands there is quite a bit of circumstantial evidence. While that is enough to convict, it is enough to support my comment as an expression of opinion.

Fact of the matter is, I'd recuse myself from that jury because I can acknowledge my inability to be impartial. I have had no problem serving on two other juries and remaining impartial to emotional testimony and sticking to the facts.

Re:I find him rather rude (1)

anton_kg (1079811) | more than 7 years ago | (#20026343)

I would say he is rather "fair" rude. Most of the time I agree with him and would say the same to a friend. Sometimes it even make me laugh. I admire his ability to negotiate a high level (political) stuff and continue to write a low level code. And it's not because he produces a well know product.

RTFA and understand (4, Insightful)

realdodgeman (1113225) | more than 7 years ago | (#20025687)

I find Linus' comments very interesting, and very honest. He has good arguments, and to me it seems like he did the right thing. He is even open to change scheduler if someone can prove that SD does a better job than CFS, and get someone reliable to maintain it.

Linus admitted to favoritism (5, Insightful)

Anonymous Coward | more than 7 years ago | (#20025877)

Whatever way you want to paint it, that's exactly what he did.

He believes that Ingo is a more reliable maintainer, so he chose Ingo's few-day old hack instead of Con's very mature and well tested scheduler.

Personally, I think that the person who is at fault here is Ingo, because he has a "Not Invented Here / By Me" mentality, and instead of developing Con's scheduler further, he totally objected to Con's work for ages (which prevented it from getting into mainline), and then suddenly saw the light and wrote his own quick hack based on the same design.

Ingo may be a good developer and maintainer, but he sure as hell isn't a friendly co-developer.

Re:Linus admitted to favoritism (0)

Anonymous Coward | more than 7 years ago | (#20026169)

And given what happened, Linus is not proven wrong... quite the opposite.

Re:RTFA and understand (2, Interesting)

arth1 (260657) | more than 7 years ago | (#20025945)

As long as it's not anything like the CFQ IO elevator, which has turned out to slow down and increase critical latencies on every system I've tested it on, compared with deadline and anticipatory schedulers. This seems to be especially true for hard working (i.e. underpowered) systems, where the need for a good IO scheduler is higher.
I know, IO and job scheduling are two different things, but I still hope the "completely fair" naming part is coincidental, and not a promise of similarity.

Re:RTFA and understand (-1, Flamebait)

Cyberax (705495) | more than 7 years ago | (#20025981)

I'm sorry, but his arguments are CRAP.

First of all, Con Kolivas was more than willing to maintain his code (see answers to Linus's post).

Second, CFS is SLOWER THAN THE OLD SCHEDULER on some workloads. It's quite noticeable on gaming workloads. Or non gaming, see [] - 80% regression on one benchmark.

No scheduler is going to be ideal. That's the fact.

But Con Kolivas also had pluggable scheduler architecture which would have allowed to use the most fitting scheduler for some workloads.

Guess what? Ingo+Linus rejected it, because it gives too much freedom of choice.

Re:RTFA and understand (2, Informative)

the_greywolf (311406) | more than 7 years ago | (#20026283)

A few moments ago, Linus posted a message explaining why he rejected plugsched: He detests politically-motivated code.

So I absolutely detest adding code for "political" reasons.

I personally feel that modal behaviour is bad, so it would introduce what is in my opinion bad code, and likely result in problems not being found and fixed as well (because people would pick the thing that "works for them", and ignore the problems in the other module).

And while I disagree with the choices he made regarding SD and plugsched, I do see his point: Each of those schedulers would become too specialized and would ignore the issues exposed in other workloads. SD works extremely well in most situations, but has trouble in specific high-load server environments. CFS, likewise, has problems with desktop usage. Both developers had different goals.

(I just think Con met goals beyond his own better than Ingo did.)

Re:RTFA and understand (1)

Cyberax (705495) | more than 7 years ago | (#20026397)

The problem is that server environments are going to be always different from desktop ones. CFS alleviates this to a certain degree with (guess what?) pluggable scheduling policies. But it's not going to be better than a dedicated pluggable scheduler framework.

So we're going to have good server performance and sucky game performance, because none of the maintainers care about gaming.

"aimed at improving the desktop experience" (0)

Anonymous Coward | more than 7 years ago | (#20025701)

As a computer geek who first started using linux as a learning tool, and then used it as a server alternative back in the days when SCO and Unixware were the only "unix" options on Intel/AMD CPUs, I'm starting to hate the new desktop direction/hype Linux is taking. And it has nothing to do with the fact that under Centos5 x86_64, my new 2xE5320 Xeon, 8G of memory seems to be just as fast as Centos5 on Dual Xeons (2.4Ghz), 4G :(

Enough alerady with Linux and the desktop. Let the desktopers use MS or Mac.

Re:"aimed at improving the desktop experience" (2, Interesting)

Anonymous Coward | more than 7 years ago | (#20026241)

Linus slightly disagrees. From TFA:

People are suggesting that you'd have a separate "desktop kernel". That's
insane. It also shows total ignorance of maintainership, and reality. And
I bet most of the people there haven't tested _either_ scheduler, they
just like making statements.

The fact is, I've _always_ considered the desktop to be the most important
And I suspect that that actually is true for most kernel developers,
because quite frankly, that's what 99% of them ends up using. If a kernel
developer uses Windows for his day-to-day work, I sure as hell wouldn't
want to have him developing Linux. That has nothing to do with anything
anti-windows: but the whole "eat your own dogfood" is a very fundamental
thing, and somebody who doesn't do that shouldn't be allowed to be even
_close_ to a compiler!

[emphasis mine]

I'm gonna have to go with Linus on this one.

Re:"aimed at improving the desktop experience" (0)

Anonymous Coward | more than 7 years ago | (#20026471)

I'm with you. Linux doesn't "need" a better desktop, and it doesn't need gaming. Those are ego concerns of people who are ego-identified with Linux and want to see it take over the world for their own ego gratification. That kind of thinking has nothing at all to do with the continued success of Linux in meeting the needs of its real users.

I certainly hope Linux keeps improving on the desktop, because I use it, but if Linux remains mediocre on the desktop for the foreseeable future, that is no threat to its success and not much of a usability annoyance (as distinct from an ego blow) for its users.

Why not have both? (0)

Anonymous Coward | more than 7 years ago | (#20025723)

Can someone explain to me why it can't be a kernel option to choose between these two schedulers?

Re:Why not have both? (1)

orkysoft (93727) | more than 7 years ago | (#20025787)

It already is an option in recent kernels to change to the completely fair scheduler. In fact, I'm using it right now, and it seems better at some things, and worse at other things, which is to be expected.

tfa shows "interesting" view into Linus's outlook (5, Insightful)

Anonymous Coward | more than 7 years ago | (#20025811)

It's an interesting set of emails. In addition to admitting that he actually didn't have any problem with the SD code, Linus points out that he made a gut call that Con is difficult to deal with without even looking into it because, apparently on near religious grounds, he doesn't believe in reading "specialized" mailing lists. What i find of concern is that he'd express such strong opinions about people basically without having even spent an hour or two browsing some list archives. Further, he seems perfectly aware that he may have heard just one side of the story, and yet he STILL doesn't feel he needs to look into it further or to soften his view? WTF ?

Has Linux kernel development always been this ... arbitrary ?

From TFA (actually form the quoted emails) after several mails where Linus has been bashing this Con Kolivas guy for not taking feedback and being argumentative, and then offers some statements about the virtues of a good maintainer some guy "Kasper Sandberg" asks him:

"Okay, i wasn't going to ask, but i'll do it anyway, did you even read the
threads about SD?"

to which Linus responds:

"I don't _ever_ go on specialty mailing lists. I don't read -mm, and I
don't read the -fs mailing lists. I don't think they are interesting.

And I tried to explain why: people who concentrate on one thing tend to
become this self-selecting group that never looks at anything else, and
then rejects outside input from people who hadn't become part of the 'mind

That's what I think I saw - I saw the reactions from where external people
were talking and cc'ing me.

And yes, it's quite possible that I also got a very one-sided picture of
it. I'm not disputing that.

Damn right the desktop experience is improved! (3, Interesting)

Anonymous Coward | more than 7 years ago | (#20025827)

You can be pretty damn right that the desktop experience is improved with Ingo Molnar's scheduler! If you have done any serious audio work on any platform you know that Linux kernel + Ingo Molnar's IO scheduler = the best platform for serious audio work. This combination has the lowest latencies. Linux kernel+Ingo Molnar's IO scheduler+Ardour [] offers currently lowest latencies and the best of all - it's completely free! It is pretty amazing - really. Every true professional audio engineer will agree with me.

Re:Damn right the desktop experience is improved! (1)

Chainsaw (2302) | more than 7 years ago | (#20025939)

Except for the TRUE professional audio engineers. You know - the ones who have spent absurd amounts of money on Pro Tools gear.

Re:Damn right the desktop experience is improved! (1, Funny)

Anonymous Coward | more than 7 years ago | (#20025975)

Hehe, ;) you are right. Their ProTools hardware just has to be better, because it costs so much :)

Why does Linus appear so angry? (1)

OzPeter (195038) | more than 7 years ago | (#20025889)

(Disclaimer - I have never met Linus or heard him speak on anything )

After reading over the article, I came away with the impression that Linus appears to be an angry person. I have also noticed this in past topics where emails from Linus have been mentioned. So I am asking the question as to why he appears this way. Is it because I always see such references at particular time like now with hot button issues? Or perhaps because English is not his native tongue? Or is it because he really does have an anger management issue?

Based on his own comments in those emails (and the standards that he seems to hold everyone to) it seems to me that Linus would not work with himself as he himself appears very pig-headed and stubborn.

Anyone care to explain?

Re:Why does Linus appear so angry? (1)

vertinox (846076) | more than 7 years ago | (#20026297)

After reading over the article, I came away with the impression that Linus appears to be an angry person.

If you grew up in Finland, you'd be angry too. ;)

But seriously, I knew one person from Finland who explained to me that due to their proximity to the Arctic circle and lack of daylight made them have a high rate of depression in Helsinki. He lives in San Jose these days so I don't know what is up with that. Maybe its the traffic that gets to him.

Why not both? (4, Interesting)

rm999 (775449) | more than 7 years ago | (#20025901)

Why can't there be a flag that determines what scheduler is used at runtime, with both schedulers built into the kernel? I thought the whole point of Linux is that it is customizable and modular - I know this doesn't necessarily apply to the kernel, but why not?

I know very little about operating systems, schedulers, and maintaining large projects, so please excuse any ignorance in my post ;)

Re:Why not both? (4, Informative)

MBCook (132727) | more than 7 years ago | (#20026207)

Linux doesn't support that, as far as I know. There are variables you can tune though. More on this later.

Something like that is very risky. Where as a filesystem can be used or not, and the code is only hit when accessing it, the scheduler is used constantly. If the scheduler could be switched at runtime, that means that either you have to have some kind of if statement on every scheduler entry point, or hide it all behind a pointer and a structure. Either one isn't as efficient as just having it hard wired in. You also have the complexities of being able to hand stuff off from one scheduler to another. Also, debugging get much harder (you have problem with slowness X, now which of the 3 schedulers are you using? Which version? What are the variables set to?).

As for selectable at compile time, that means you have a have a well designed interface that lets you swap things out. That means it either has to be generic, or would favor one scheduler to the detriment of others. Sometimes this tradeoff is acceptable, sometimes it isn't.

Now my understanding on this is that Linux doesn't support plugging in full schedulers. There were patches for that a few years go. Linus and others (Ingo especially, I think) said no, and the patches never made it in. Recently a system was developed that would allow a part of the scheduler to be plugged in. This way it could be better tuned for different workloads, without the full detriment of a full pluggable scheduler. This was done recently, and they were called out on this flip and explained quite well how they were a little hard, and this was a little different.

Go read LWN [] 's kernel pages. They talked about this in the last month or so, so it should be available to non-subscribers by now (although you should subscribe, they're great).

Re:Why not both? (2, Insightful)

r_jensen11 (598210) | more than 7 years ago | (#20026395)

I'm voting for keeping it selectable when compiling the kernel.

You talk about a program favoring one scheduler over another or using generic calls. There are tons of programs out there already, without this new scheduler in mind, and they are running better than with the old scheduler. After this scheduler becomes common-placed, I'm sure the then-new programs will have some examples of running better with the old scheduler.

Keep both schedulers in the kernel, but only allow the users or the distributions to build one into the running kernels. This way it's the best of both worlds.

Supervillain (3, Funny)

EnsilZah (575600) | more than 7 years ago | (#20025961)

Come on, it's quite obvious that Linus's secret superhero alter-ego has done battle with Kolivas' supervillain identity before (I mean, Con Kolivas? Do the writers even try to make these things sound authentic?) and is now trying to thwart his evil plans of global domination.

Hope it does something (0)

Anonymous Coward | more than 7 years ago | (#20026009)

In Debian Etch the basic scheduler could have some serious improvements. At first things were fine and I expected to be happy with Debian Etch and use klik to run cutting edge Debian packages in user space but as things were made ready for the server target market plug and play Wacom use was removed and smooth audio play simply dissapeared, fades in Amarok stutter at start and end. klik was never made to work on Etch, so it seems server client deployments are the focus and the individual desktop is left behind. I won't be switching until this new kernel has become in use across distros.

Somehow in all what the three have said.... (2, Insightful)

3seas (184403) | more than 7 years ago | (#20026015)

... I find a bit of hypocrisy.

Three is right, as its Con and an email exchange between Linus and another.

Whooo hooo..

That settles it.... everybody is accounted for..... right??

Its open source but with all the talk about having a maintainer of certain character as a part of the consideration of .... consideration about inclusion of code they wrote.. Uhhh did I forget to say its "Open Source"?
Its not uncommon for pioneers to be forgotten as what comes next, takes over...
Or does this mean that when a maintainer dies, so does what they were maintaining?

The general message Con seemed to be expressing was more interesting as a general observation than of specific code.

The response from Linus suggest that although Linus does not frequent specific topic lists because of inherent bias, he has his bias none the less.

There is a general across the board bias, proprietary and open source, and it is one of exclusion of the end users.
And it comes across as arrogance motivated by money and/or ego.

To explain, programming is an act that includes creating functionality that is then accessible thru an easier to use interface such as a function call with arguements and expected return value. The general concept is common knowledge in coding regardless of what programming language you are using,

However, this concept is not typically provided to the end user, but instead kept away from the user and certainly not provided to the user, when some distortion of it is provided the user, in any sort of easy common consistent manner.

To clarify, users access programs typically via a command line or GUI. Neither of which are so conducive to allowing teh users to put things together for themselves. All the functionality if available to the user via the programs GUI or command line. But the same functionality is not available in an mode that allows user to call the functionality in the program and make use of the results outside of teh programs command line or GUI interface.

Con mentioned the Amiga. The Amiga had all three user interfaces. The command Line, The GUI and the missing user interface an every other system today, The IPC port interface, most commonly known as the AREXX port but did not need AREXX running in order to use the port for "user putting things together for themselves".


Cause you can dumb down the user and get ideas from them and sell those ideas implemented, back to them.

But when you take away from the users, the ability to put things together for themselves, then that makes you a hypocrite when you then call them ignorant, armchair coders or any other demeaning term. As it is you who have created that self supported dependency of trying to justify your lack of inclusion of others.

Con outright stated how he got started.

Maybe You linus and a whole world of other coders, need to pull you head out of your asses and SERIOUSLY realize, THERE ARE OTHERS you are not considering.

Ultimately, if people want to optimize their system for their needs, they should be able to. But there is serious prevention of that across the board.

Re:Somehow in all what the three have said.... (1)

shaitand (626655) | more than 7 years ago | (#20026147)

'The general concept is common knowledge in coding regardless of what programming language you are using,

However, this concept is not typically provided to the end user, but instead kept away from the user and certainly not provided to the user, when some distortion of it is provided the user, in any sort of easy common consistent manner.'

Remind me again WTF that has to do with scheduling and desktop performance?

Re:Somehow in all what the three have said.... (1)

3seas (184403) | more than 7 years ago | (#20026391)

small minds see only small pieces of a bigger picture....

As an outsider to kernel development, I'm curious (1)

professorfalcon (713985) | more than 7 years ago | (#20026029)

Is the Linux development model more like Surf's Up [] or Happy Feet [] ?

"recently released"? (0)

Anonymous Coward | more than 7 years ago | (#20026071)

The scheduling debate is the lost prophecy of John Titor!

I apparently missed something (1)

shaitand (626655) | more than 7 years ago | (#20026111)

I am not a kernel developer and do not follow the mailing list. I was under the impression that a new scheduler that was supposed to drastically improve performance went into the kernel a couple years ago? I know there has been a huge difference in desktop performance from that time.

Best of Both Worlds (1)

Forty Two Tenfold (1134125) | more than 7 years ago | (#20026303)

Any "reasonable" reason why they couldn't integrate both?

say again? (0)

Anonymous Coward | more than 7 years ago | (#20026357)

"Schedulers are actually not at all that important
in the end: they are a very very small detail in the kernel."

lol. crips .. i'm dying from laughter.

seems like somebody has been in the usa too long ... dude, i'm watching your
ship sink. hilerious. honestly.
freakin' americans, sheesh ...

If Linux sucks on the desktop (3, Insightful)

forgoil (104808) | more than 7 years ago | (#20026387)

Start profiling the damn thing! Write performance tests, good ones, write really evil stress tests, stress the crap out of it, and then you will know what is *wrong*. Might not be the kernel at all, in fact, I think that a lot will be because of applications (always a huge source for problems), the UI/Graphics subsystem (again, huge source for trouble, X11, drivers, UI toolkits, they all tend to be far from perfect) and such.

But pissing and moaning won't do you any good. At least Con did try to write stuff, but not being a professional software engineer hurt his efforts I'm assuming. The guy would probably make a good technical manager though. It is a shame he felt he had to quit, it would have been much better if he could have gotten a few other kernel hackers on with him to go on. I think he ended up with a lot of users backing him, but no coders :(

Not that I am a Linux person, but I always find it sad to see people who are really into something quitting for bad reasons (bad in the sense that the shouldn't have to, not that he did something unwise).

Linus ir right (0)

Anonymous Coward | more than 7 years ago | (#20026401)

I am with Linus on this one. For the life of me I can't understand what this sucking up to RMS is about. Linus himself does not think GPLv3 is a good thing. So why do people keep adopting it.
Linux without Linus cannot succeed. A lot of young folks don't realize this. RMS can't advance the cause of Linux like Linus does.

Linus is a piece of shit (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#20026413)

And you still wonder about linux not dominating the desktop?
Bill is a thousand times better dictator than this scandinavian junk.
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