Eric Saxe wrote:

> Author: Eric Saxe <eric.saxe at sun.com>
> Repository: /hg/tesla/pad-gate
> Latest revision: 2d413ada02d115b917bcb2b221652d6836cd10af Total
> changesets: 1 Log message:
> Dispatcher driven P-state management under simple policy
> 
> Files:
>       update: usr/src/uts/i86pc/io/cpudrv_plat.c
>       update: usr/src/uts/i86pc/os/mp_machdep.c
>       update: usr/src/uts/i86pc/os/mp_startup.c
>       update: usr/src/uts/i86pc/sys/cpudrv_plat.h
>       update: usr/src/uts/i86pc/sys/machcpuvar.h

The policy seems not to be good.
It prevents the core from going into idle. When the new kthread is idle
thread,
the policy will change the power state to low power state, this calls
speedstep
power interface on IA platform, which is implemented by xcall. the core
may
spend some time to grab highest mutex here.

P-state policy implemented in cmt thread switch here seems not to be a
good
idea. We can't upgrade or downgrade the speed level just by the old
thread or
the new thread is idle thread. We probably still need change it
according to the
system workload.

Thanks,
-Aubrey


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