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ULE Now The Default Scheduler On FreeBSD

Posted by timothy on from the ule-stole-my-prom-date dept.

Dan writes "FreeBSD's Jeff Roberson says that the ULE scheduler has entered into its probationary period as the default scheduler on FreeBSD. He says that if all goes well, it will remain the default through the rest of FreeBSD 5.* releases. He is requesting you to switch over and test it. The ULE scheduler was designed to address the growing needs of FreeBSD on SMP/SMT platforms and under heavy workloads. It supports CPU affinity and has constant execution time regardless of the number of threads."

9 of 134 comments (clear)

  1. Good news by Zork+the+Almighty · · Score: 4, Funny

    This is great news. The O(1) scheduler in Linux is awesome, and it's good to see FreeBSD keeping up. Now if we just had an O(1) way to squash *BSD trolls, Slashdot would be saved.

    --

    In Soviet America the banks rob you!
    1. Re:Good news by Bobas · · Score: 5, Interesting

      I'm testing this scheduller now (option SCHED_ULE in kernel config) on GNOME desktop. You can really tell the difference, feels much "smoother" and "faster".

      Just my 2c.

  2. "a pathological case" by bersl2 · · Score: 4, Interesting
    Quoted from the ULE paper (p.11):
    Figure 6 illustrates a pathological case for the Linux
    scheduler which early versions of ULE fell victim to.
    The setup is 5 nice -5 processes each attempting to use
    25% of the CPU. This over-commits the CPU by 25%,
    which should not be a problem. However, since Linux
    gradually reduces the priority until it hits the minimum,
    the nice value is enough to prevent even normal
    interactive tasks from running with reasonable latency.
    This was solved in ULE by using the interactivity
    scoring algorithm presented above.
    I didn't follow the development of the O(1) scheduler very closely. Has this been looked at since 2.5.56 (the version of Linux they cite)? Is this even true?
  3. Does everyone know about GNU/KFreeBSD? by ciaran_o_riordan · · Score: 4, Interesting

    GNU/KFreeBSD is a project that doesn't get enough press.

    Most GNU systems use Linux as their kernel, but this doesn't have to be the case. The porting of GNU to the FreeBSD kernel is almost complete. (the project name changed from GNU/FreeBSD to GNU/KFreeBSD after a trademark discussion with some FreeBSD folks.)

    FreeBSD people say that their kernel is rock solid, has the best uptimes, most robust networking, and now it's getting an improved scheduler. So it would make sense for GNU users to considering using the FreeBSD kernel instead of Linux.

    Having everyone using the same kernel just makes life easier for worm writers, and corporate attacks such as the SCO fiasco.

    Of course, adoption will be hampered by the marketing mistake of calling the whole OS "Linux", but I hope that choice of kernels will become more normal in the future. It would also help if they came up with a friendlier name than "GNU/KFreeBSD" (8 sylabyls!).

    Anyway, I hope to start using the FreeBSD kernel soon.

    --
    Expert in software patents or patent law? Contribute to the ESP wiki!
    1. Re:Does everyone know about GNU/KFreeBSD? by Homology · · Score: 5, Informative
      So, the OpenBSD guys are wasting their time rewriting software that already exists in a free form, and you're questioning the benefit of the GNU/KFreeBSD project?

      The point is : They don't see GPL as free enough. And since OpenBSD, like other BSD, is not just a kernel, they have to care about licenses for all program shipped with their OS. Go check OpenBSD Copyright Policy

    2. Re:Does everyone know about GNU/KFreeBSD? by anthonyrcalgary · · Score: 4, Informative

      Well, they actually *do* help keep the GNU toolset portable and clean. Even if they aren't used, using the same stuff on more than one OS exposes problems before they become a remote root exploit.

      Sure I like BSD. Says so in my sig. But if someone else does things right, I'm not going to yell at them.

      Besides, with the GNU toolset on the FreeBSD kernel, you can set up a jail on the FreeBSD side, and then if you want both you can have both. There are differences, it's annoying sometimes, I'm sure some people want both.

      --
      When someone might yell at me, it has to be OpenBSD.
    3. Re:Does everyone know about GNU/KFreeBSD? by scrytch · · Score: 4, Interesting

      Besides, with the GNU toolset on the FreeBSD kernel, you can set up a jail on the FreeBSD side, and then if you want both you can have both. There are differences, it's annoying sometimes, I'm sure some people want both.

      Are you aware that /compat/linux will work just fine in a jail, and that the Linux distribution in there (you get your choice of redhat or debian) runs a rull suite of GNU utilities? And it's all at native speed, not emulated, it's going through the same syscall mapping layer that BSD itself uses.

      I'm all for porting the GNU toolchain to BSD, and so are a lot of other people, which is why it's already been done and is available in ports. Are you seriously talking about porting bloatsome abominations like glibc or something? (Oh wait, /compat/linux again, been done)

      --
      I've finally had it: until slashdot gets article moderation, I am not coming back.
  4. Why? by bluGill · · Score: 4, Interesting

    I uise freeBSD everyday, and I have to ask why you would care about GNU/freeBSD. The utilities are essentially equivelent. There is a little more bloat (read features) in some of the GNU stuff. Nothing really significant though.

    Sure it is neat that they can do it. However to say everyone should want to run it? I don't get it.

  5. Re:Sounds like a big improvement by sirket · · Score: 4, Interesting

    1. is the most SMP scalable (parallel)

    Long term or short term? Linux is faster now but the BSD folks always seem to spend a lot more time actually researching the issue.

    2. is the most algorithmically scalable

    I don't even know what this means. Are you referring to the scheduler and other system processes? Linux has an O(1) scheduler - only it ran head first into a brick wall in certain instances. FreeBSD spent a _lot_ of time implenting a robust and stable scheduler and it shows. NetBSD looked at the Linux algorithmns and tied or beat them in every case.

    3. has fastest single threaded performance

    How about which OS is more stable? How about which OS didn't have an idiotic 2TB block device limit for years longer than the BSD's? How about which OS didn't have a 2GB file size limit?

    4. runs on more architectures

    Can you say NetBSD? Besides which, the only computers I own are DEC Alphas and x86 boxes. I could cares less which OS runs on the DreamCast.

    5. supports the most hardware

    How about which one supports the hardware you actually want to run on, and not the toaster in your basement.

    6. has the fastest TCP/IP stack

    For what application? You ask this question as if there is one TCP stack that is fastest in all applications. You also probably prefer a fast stack to a stable one.

    Answers won't be accepted without evidence.

    Questions won't be accepted from AC's. Besides, if you want answers, go look them up yourself.

    -sirket