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Replacing Atime With Relatime in the Kernel

Posted by ScuttleMonkey on from the results-apparently-too-much-to-ask-for dept.

eldavojohn writes "Our friend Jeremy at the Kernal Trap has dug up some interesting criticism of atime from Linus Torvalds. As Linus submitted patches to improve relatime he noted: 'I cannot over-emphasize how much of a deal it is in practice. Atime updates are by far the biggest IO performance deficiency that Linux has today. Getting rid of atime updates would give us more everyday Linux performance than all the pagecache speedups of the past 10 years, _combined_.' And later severely beat atime about the head with a pointed stick: 'It's also perhaps the most stupid Unix design idea of all times. Unix is really nice and well done, but think about this a bit: 'For every file that is read from the disk, lets do a ... write to the disk! And, for every file that is already cached and which we read from the cache ... do a write to the disk!'" Well, I guess I can expect my Linux machine to become a little bit faster!"

8 of 416 comments (clear)

  1. Re:Linus did not say that! by Anonymous Coward · · Score: 5, Funny

    My name is Ingo Molnar and you mis-attributed my quote. Prepare to die!

  2. You fell victim to one of the classic blunders! by stefanlasiewski · · Score: 5, Funny

    "You fell victim to one of the classic blunders! The most famous is never get involved in a flame war on Kerneltrap..."

    --
    "Can of worms? The can is open... the worms are everywhere."
    1. Re:You fell victim to one of the classic blunders! by dcapel · · Score: 5, Funny

      A Slashdot summary wrong? Inconceivable!

      --
      DYWYPI?
  3. Re:latest relatime patch by Anonymous Coward · · Score: 5, Funny

    I agree - modifying a text file is a messy complicated business only suitable for the elite super hackers out there. It's much simpler for me to apply the patch and recompile the kernel.

    I kid, I kid.

  4. atime on EXT3, huh? by Trogre · · Score: 4, Funny

    (mount ext3 filesystem with noatime flag)

    $ time for i in `seq 1 10000`; do touch file1.dat; done

    real 0m15.231s
    user 0m3.075s
    sys 0m11.970s

    $ time for i in `seq 1 10000`; do cat file1.dat >>/dev/null; done

    real 0m14.326s
    user 0m2.928s
    sys 0m11.172s

    (remount without noatime flag)

    $ time for i in `seq 1 10000`; do touch file1.dat; done

    real 0m12.629s
    user 0m2.687s
    sys 0m9.772s

    $ time for i in `seq 1 10000`; do cat file1.dat >>/dev/null; done

    real 0m12.401s
    user 0m2.624s
    sys 0m9.624s

    Yes I think I'll stick with atime for now, thanks Linus.

    --
    "Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
  5. Re:Ummm.. by nschubach · · Score: 5, Funny

    $ man mount

    How can anyone write that with a straight face?
    --
    Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
  6. Re:Ummm.. by PopeRatzo · · Score: 4, Funny

    I have the noatime line in my fstab.
    Ah, these are the kind of stories I first starting coming to Slashdot for.

    I don't think you can fully realize how poetic a phrase such as the one above can be until you read it with absolutely no understanding, as I do.

    Thank you, ArcherB and thank you, Slashdot.
    --
    You are welcome on my lawn.
  7. Re:Ummm.. by misleb · · Score: 5, Funny

    How can anyone write that with a straight face?


    I'm sure it was written with a gay face.

    --
    "THERE IS NO JUSTICE, THERE IS ONLY ME." -Death