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SubjectRe: How to measure time accurately.
Peter Chubb wrote:
>>>>>>"Chris" == Chris Friesen <> writes:

> Chris> Most cpus have some way of getting at a counter or decrementer
> Chris> of various frequencies. Usually it requires low-level hardware
> Chris> knowledge and often it needs assembly code.
> As a device driver is inside the linux kernel (unless you're writein a
> user-mode device driver :-)) you can use the getcycles() macro that's
> defined for most architectures. It provides a snapshot of the
> cycle-counter.

For ppc this only gives 32-bit values, which overflow every 129 seconds
on my G5. Depending on how long you're trying to time, this could be a

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