mwait-idle: fine-tune IVT residency targets

mwait-idle: fine-tune IVT residency targets

Ivy Town processors have slightly different properties
than Ivy Bridge processors, particuarly as socket count grows.
Here we add dedicated tables covering 1-2 socket,
3-4 socket, and > 4 socket IVT configurations.

This reduces the frequency of deep transitions on those systems,
which can impact throughput.

Signed-off-by: Len Brown <len.brown@intel.com>
Socket count determination needs to be done differently for us: The
relevant code runs in a pre-SMP initcall, and hence can't use
cpu_to_socket() (as only the boot CPU's cpu_data[].phys_proc_id got set
up by that time). As a replacement the patch introduces
apicid_to_socket(), thus estimating the socket count based on the boot
CPU's internal topology information (if all CPUs in a system are the
same, wich ought to be the common case, this estimate will be precise).

Note that apicid_to_socket() handles Intel topology determination only
for now, as the mwait-idle driver currently only supports Intel CPUs.

Signed-off-by: Jan Beulich <jbeulich@suse.com>