Re: do_gettimeofday vs. rdtsc in the scheduler

From: David S. Miller (
Date: Tue Sep 17 2002 - 15:54:51 EST

   From: Andi Kleen <>
   Date: 17 Sep 2002 23:00:38 +0200
   Also reading HPET is somewhat more costly than reading TSCs because it
   goes to the southbridge, so there are cases where using TSC is
   probably better (e.g. I think for networking packet time stamping the
   TSC is just fine with all its limitations)

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) :-)
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