Messages in this thread | | | Date | Tue, 7 Dec 2004 18:00:33 -0800 | From | Andrew Morton <> | Subject | Re: Time sliced CFQ io scheduler |
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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. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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