Scheduler fixes for hyperthreading

[M. Warner Losh]

In message: <20050522025914.GD1108 at empiric.icir.org>
            Bruce M Simpson <bms at spc.org> writes:
: On Sat, May 21, 2005 at 10:44:25PM -0400, Stephan Uphoff wrote:
: > Beside benchmarking - is there any other real use for RDTSC ?
: > Is there any use of RDTSC that system requiring the security cannot live
: > without? (We could even try to emulate the instruction if we really need
: > to)
: 
: A number of ports use RDTSC for high-resolution timing. The most obvious
: examples being machine emulators mostly used for gaming (UAE and MAME
: spring to mind, possibly also dosbox and others).

Which also makes it hard to emulate, since that adds a lot of
overhead to the numbers...

Warner