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    SubjectRe: [PATCH 9/11] Panic delay fix
    On Wed, 14 Feb 2007 13:53:08 -0800
    Zachary Amsden <zach@vmware.com> wrote:

    > > IDE on several platforms has performance critical paths that use
    > > ndelay(400) or failing that udelay(1)
    >
    > Ok, I buy that. A 486DX / 33 Mhz processor takes 10 cycles to issue a
    > CALL / RET pair. This is about 300ns. Is there an issue with being too
    > early to issue I/O operations or too late?

    Too early you lose, too late you just waste clock time.

    > But I fail to see how such careful timing can be done at this
    > granularity on such hardware without well tweaked assembly code.

    Thats what is used most platforms use udelay(1) in fact however
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