i386 and amd64 mp_machdep: improve topology detection for Intel CPUs

This patch is significantly based on previous work by jkim.
List of changes:
- added comments that describe topology uniformity assumption
- added reference to Intel Processor Topology Enumeration article
- documented a few global variables that describe topology
- retired weirdly set and used logical_cpus variable
- changed fallback code for mp_ncpus > 0 case, so that CPUs are treated
  as being different packages rather than cores in a single package
- moved AMD-specific code to topo_probe_amd [jkim]
- in topo_probe_0x4() follow Intel-prescribed procedure of deriving SMT
  and core masks and match APIC IDs against those masks [started by
  jkim]
- in topo_probe_0x4() drop code for double-checking topology parameters
  by looking at L1 cache properties [jkim]
- in topo_probe_0xb() add fallback path to topo_probe_0x4() as
  prescribed by Intel [jkim]

Still to do:
- prepare for upcoming AMD CPUs by using new mechanism of uniform
  topology description [pointed by jkim]
- probe cache topology in addition to CPU topology and probably use that
  for scheduler affinity topology; e.g. Core2 Duo and Athlon II X2 have
  the same CPU topology, but Athlon cores do not share L2 cache while
  Core2's do (no L3 cache in both cases)
- think of supporting non-uniform topologies if they are ever
  implemented for platforms in question
- think how to better described old HTT vs new HTT distinction, HTT vs
  SMT can be confusing as SMT is a generic term
- more robust code for marking CPUs as "logical" and/or "hyperthreaded",
  use HTT mask instead of modulo operation
- correct support for halting logical and/or hyperthreaded CPUs, let
  scheduler know that it shouldn't schedule any threads on those CPUs

PR:			kern/145385 (related)
In collaboration with:	jkim
Tested by:		Sergey Kandaurov <pluknet@gmail.com>,
			Jeremy Chadwick <freebsd@jdc.parodius.com>,
			Chip Camden <sterling@camdensoftware.com>,
			Steve Wills <steve@mouf.net>,
			Olivier Smedts <olivier@gid0.org>,
			Florian Smeets <flo@smeets.im>
MFC after:		1 month

0 files changed, 0 insertions, 0 deletions