G5 timebase_frequency

Michal Ostrowski mostrows at watson.ibm.com
Sun Feb 8 09:40:38 EST 2004

I've noticed that timebase_frequency on a G5 appears to be defined by OF
to be 33.3333MHz. OTOH, the specs for the 970 claim that timebase has a
frequency of 1/8 that of the CPU clock rate.  So, on a 2.0GHz processor
timebase would be 250MHz.

Which one of these, if any is correct?

My guess would be to say 250MHz, but my experiments show that a clock
based on timebase, assuming that rate, appears to be about 10% slow.

Michal Ostrowski <mostrows at watson.ibm.com>

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