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    SubjectRE: Direct io on block device has performance regression on 2.6.x kernel
    Andrew Morton wrote on Wednesday, March 09, 2005 5:34 PM
    > What are these percentages? Total CPU time? The direct-io stuff doesn't
    > look too bad. It's surprising that tweaking the direct-io submission code
    > makes much difference.

    Percentage is relative to total kernel time. There are three DIO functions
    showed up in the profile:

    __blockdev_direct_IO 4.97%
    dio_bio_end_io 2.70%
    dio_bio_complete 1.20%

    > hm. __blockdev_direct_IO() doesn't actually do much. I assume your damn
    > compiler went and inlined direct_io_worker() on us.

    We are using gcc version 3.4.3. I suppose I can finger point gcc ? :-P

    - Ken

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