Re: do_gettimeofday vs. rdtsc in the scheduler

Alan Cox (alan@lxorguk.ukuu.org.uk)
17 Sep 2002 22:28:12 +0100


On Tue, 2002-09-17 at 21:54, David S. Miller wrote:
> The cpu gets a bus clock input, so the system tick should be processor
> local as much as TSC is.
>
> It's boggling that this is being messed up so much. I can't believe
> Sun got something incredibly right (Ultra-III has a system tick) :-)

A bus clock - but things like the x440 have more than one bus clock. Its
NUMA. Also the bus clock and rdtsc clock are different - rdtsc is
dependant on the multiplier. Shove a celeron 300 and a celeron 450 in a
BP6 board with tsc on and enjoy

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