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    SubjectRe: Memory mapped IO vs Port IO
    On Fri, Sep 12, 2003 at 11:58:07AM -0700, Martin J. Bligh wrote:
    > >> Also - a perhaps more useful test is a write followed by a read.
    > >
    > > Well, someone else will have to run that test. On Altix, a read() is
    > > freakishly expensive, and I'm not really interested in showing everyone
    > > how bad it is ;)
    > I find percentile comparisons useful for hiding the embarassement
    > of occasional hardware realities ;-) (ie what's the speed *ratio*
    > between the two types of read).

    Well, in our case, read() and in() will be pretty close,
    percentage-wise. The read() in itself is so bad that I think the
    additional badness of in() will be mostly hidden.

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