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    Subjectstat benchmark
    From
    Date
    At

    http://www.daimi.au.dk/~sandmann/stat-benchmark.c

    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.

    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
    information.

    Does this sound like a reasonable idea?


    Thanks,
    Soren


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