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    SubjectRe: O_DIRECT question
    Hello!

    > Maybe you need to say why you want to use O_DIRECT with its terrible
    > performance?

    Incidentally, I was writing an external-memory radix-sort some time ago
    and it turned out that writing to 256 files at once is much faster with
    O_DIRECT than through the page cache, very likely because the page cache
    is flushing pages in essentially random order. Tweaking VM parameters
    and block device queue size helped, but only a little.

    Have a nice fortnight
    --
    Martin `MJ' Mares <mj@ucw.cz> http://mj.ucw.cz/
    Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
    Linux vs. Windows is a no-WIN situation.
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