On Tue, 2008-10-14 at 18:17 +0900, Tejun Heo wrote: > kenneth johansson wrote: > > On Mon, 2008-10-13 at 18:33 -0700, Grant Grundler wrote: > >> On Mon, Oct 13, 2008 at 3:19 PM, kenneth johansson <ken@xxxxxxxxx> wrote: > >> ... > >>>> Can you try "dd oflag=direct if=/dev/null of=/dev/sdb bs=64k"? > >>> I changed to use O_DIRECT and it's much more consistent now. 69-75 with > >>> 74 about 95% of the time. > >> That's low but it could be worse. Many things can contribute to slow > >> disks. > > Well my main problem was that it was fluctuating so much that can't be > > right. > Can you try deadline scheduler? > I did but it was so bad I restarted my computer and did it again. Same result complete disaster. so fas O_DIRECT is the only one that is as it should be. Alan mentioned a patch by Arjan van de Ven anyone knows how to find that one?
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