resolution profiling on Pentiums. On a 100MHz Pentium, the resolution
is at best 10 ns and actually a few hundred ns, but units of 10's or
100's of ns would be inconvenient and the current units of 1 us are a
bit too coarse.
underscore. Use it to avoid seeing badsw when profiling the kernel.
Print times more accurately (e.g. usec in %8.0f format instead of
msec in %8.2f format for averages) if hz >= 10000. This should have
no effect now since profhz is only 1024.
