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    SubjectRe: stat benchmark

    On Thursday 2008-04-24 22:59, Soeren Sandmann wrote:
    >there is a simple program that will measure the time it takes to stat
    >every file in the current directory with a cold cache.
    >This is essentially what applications do in a number of common cases
    >such as "ls -l", nautilus opening a directory, or an "open file"
    >dialog being showed.

    Mh somewhat. Some programs/libraries unnecessarily stat No, nautilus is excluded

    >Unfortunately, performance of that operation kinda sucks. On my system
    >(ext3), it produces:
    > c-24-61-65-93:~% sudo ./a.out
    > Time to readdir(): 0.307671 s
    > Time to stat 2349 files: 8.203693 s
    >8 seconds is about 80 times slower than what a user perceives as
    >"instantly" and slow enough that we really should display a progress
    >bar if it can't be fixed.
    >So I am looking for ways to improve this.
    >Under the theory that disk seeks are killing us, one idea is to add a
    >'multistat' system call that would allow statting of many files at a
    >time, which would give the disk scheduler more to work with.
    >Possibly the same thing would need to be done for the getxattr
    >Does this sound like a reasonable idea?

    XFS for example already has bulkstat, but it is not really
    exported to userspace :-/

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      Last update: 2008-04-24 23:47    [W:0.024 / U:114.208 seconds]
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