Re: X15 alpha release: as fast as TUX but in user space (fwd)

David S. Miller
2001-04-30T07:02:44Z

dean gaudet writes:
> i was kind of solving a different problem with the code page though -- the
> ability to use rdtsc on SMP boxes with processors of varying speeds and
> synchronizations.

A better way to solve that problem is the way UltraSPARC-III do and
future ia64 systems will, by way of a "system tick" register which
increments at a constant rate regardless of how the cpus are clocked.

The "system tick" pulse goes into the processor, so it's still a local
cpu register being accessed. Think of it as a system bus clock cycle
counter.

Granted, you probably couldn't make changes to the hardware you were
working on at the time :-)

Later,
David S. Miller
davem@redhat.com