Pentium microtime & SMP: A bug?

Ulrich Windl (
Thu, 2 May 1996 08:26:33 +0200

If I understand SMP in Linux right (I have only a single-processor
board), each processor can handle kernel requests (that is serve
them). The fast timing routine for the Pentium uses the cycle counter
in the processor (in the current one). Now I assume that both
processors do not start with the same cycle counter; that way the
clock offset will jump depending which processor's cycle count is
read. (I don't know if it's possible to reset a single processor)

The solution (if the problem exists) seems to be to have a cycle
counter per processor (#ifdef SMP) instead of a single one.