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    SubjectRe: Time sliced CFQ io scheduler
    Andrea Arcangeli <andrea@suse.de> wrote:
    >
    > The desktop is ok with "as" simply because it's
    > normally optimal to stop writes completely

    AS doesn't "stop writes completely". With the current settings it
    apportions about 1/3 of the disk's bandwidth to writes.

    This thing Jens has found is for direct-io writes only. It's a bug.

    The other problem with AS is that it basically doesn't work at all with a
    TCQ depth greater than four or so, and lots of people blindly look at
    untuned SCSI benchmark results without realising that. If a distro is
    always selecting CFQ then they've probably gone and deoptimised all their
    IDE users.

    AS needs another iteration of development to fix these things. Right now
    it's probably the case that we need CFQ or deadline for servers and AS for
    desktops. That's awkward.
    -
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