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    SubjectRe: [Bug 417] New: htree much slower than regular ext3
    On 7 Mar 2003, Alex Tomas wrote:

    > The problem is that getdents(2) returns inodes out of order and
    > du causes many head seeks. I tried to solve the problem by patch
    > I included in. The idea of the patch is pretty simple: just try
    > to sort dentries by inode number in readdir(). It works because
    > inodes sits at fixed places in ext2/ext3. Please, look at results
    > I just got:

    Any change in the order of dentries returned is likely to run into problem
    when seeking in a directory. Given that readdir() is usully followed by
    either zero or many stat()s, perhaps when the first stat() comes along you
    could pre-read the inodes in optimal order and cace them. However you
    tuned the size of your sort should work exactly as well as the size of the
    pre-read.

    This seems consistent with readahead and AS disk io.

    --
    bill davidsen <davidsen@tmr.com>
    CTO, TMR Associates, Inc
    Doing interesting things with little computers since 1979.

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