[tesla-dev] add current c-state support

[Li, Aubrey]

Aubrey Li wrote:

> Author: Aubrey Li <aubrey.li at intel.com>
> Repository: /hg/tesla/hpet_pcplusmp
> Latest revision: 82215f97ae6dcce62240c1236f0560773115ef13 Total
> changesets: 1 Log message:
> add current c-state support
> 
> Files:
>       update: usr/src/uts/common/os/cpu.c
>       update: usr/src/uts/i86pc/io/cpudrv/cpu_idle.c
>       update: usr/src/uts/i86pc/sys/machcpuvar.h

With this change, we can know the current cstate type on each cpu.

Thanks,
-Aubrey
=========================================================
$ kstat | grep current_cstate
        current_cstate                  C0
        current_cstate                  C3
        current_cstate                  C3
        current_cstate                  C3
        current_cstate                  C2
        current_cstate                  C3
        current_cstate                  C3
        current_cstate                  C2