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    SubjectRe: 2.6.18-rt7: rollover with 32-bit cycles_t
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    On Tue, 2006-11-07 at 17:36 -0800, Kevin Hilman wrote:
    > On ARM, I'm noticing the 'bug' message from check_critical_timing()
    > where two calls to get_cycles() are compared and the 2nd is assumed to
    > be >= the first.
    >
    > This isn't properly handling the case of rollover which occurs
    > relatively often with fast hardware clocks and 32-bit cycle counters.
    >
    > Is this really a bug? If the get_cycles() can be assumed to run between
    > 0 and (cycles_t)~0, using the right unsigned math could get a proper
    > delta even in the rollover case. Is this a safe assumption?

    Seems like the check should really be using something like time_before()
    time_after() which takes the rollover into account .. What I don't
    understand is why we don't see those on x86 ..

    Daniel

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