fstat(1) - Add support for EXT2FS filesystem.
fstat(1): fsp is in fact used.
cputimer: The freq should be sysclock_t

This prepares for 64bit sysclock_t
sio: Use sysclock_t to save value from sys_cputimer->count()
clock: Use sysclock_t to save value from sys_cputimer->count()
clock/tsc: Detect invariant TSC

According to Intel's description:
"The invariant TSC will run at a constant rate in all ACPI P-, C-. "
 and T-states. ..."

The difference between invariant TSC and constant TSC is that
invariant TSC is not affected by frequency changes and deep ACPI
C-state.

Constant TSC could be detected based on the CPU model (Intel has
the model list, while there is no information from AMD's document);
constant TSC is not detected yet.
net: Use tsc_invariant when it is necessary; mainly in time measure
bsd-family-tree: Sync with FreeBSD (NetBSD 5.2, 6.0.1, 6.0.2).
clock/tsc: Detect invariant TSC CPU synchronization

The detected result could be used to determine whether TSC could be
used as cputimer or not, and could be used by other stuffs, e.g.
CoDel AQM packet time stamping.

- Only invariant TSC will be tested
- If there is only one CPU, then invariant TSC is always synchronized
- Only CPUs from Intel are tested (*)

The test is conducted using lwkt_cpusync interfaces:
BSP read the TSC, then ask APs to read TSC.  If TSC read from any APs
is less then the BSP's TSC, the invariant TSC is not synchronized
across CPUs.

Currently the test runs ~100ms.

(*)
AMD family 15h model 00h-0fh may also have synchronized TSC across
CPUs as pointed out by vsrinivas@, however, according to AMD:

  <Revision Guide for AMD Family 15h Models 00h-0Fh Processors
   Rev. 3.18 October 2012>
  759 One Core May Observe a Time Stamp Counter Skew

AMD family 15h model 00h-0fh is _not_ ready yet.
altq: Use tsc_mpsync to detect whether TSC could be used or not
cputimer: Increase distance between priorities
fstat(1): Put the v_type -> mode_t conversion into a separate function.
fstat(1): Style changes: Remove param names from protos and staticise.
pnpinfo(1): Use errx(), use correct variable (from FreeBSD).
<vfs/tmpfs/tmpfs.h>: Hide some stuff from userland.
fstat(1): tmpfs support
cputimer: Allow MP synchronized TSC to become cputimer on x86_64

sysclock_t stays as 32bits, as suggested by dillon@.

The TSC cputimer frequency is scaled down TSC frequency (less or equal
to 128Mhz), which makes 32bits sysclock_t counter hold at least 33
seconds.

The TSC cputimer is obviously faster than other cputimers, e.g. HPET or
ACPI timer, so it has the highest priority as of this commit.  It is
enabled by default, if MP synchronized TSC is detected.  It could be
disabled by setting tunable hw.tsc_cputimer_enable to 0.
man/bnx: Add minor clarification
igb: Update man page
em/emx: Update man page