RE: CPU frequency shifting "problems"

[Jonathan Morton]

>  > APM is a lost cause, but the correct solution for ACPI systems is 
>to use the
>>  PM timer.
>
>This is _completely_ untrue.
>
>The PM timer is (a) inaccurate and (b) slow as hell.
>
>Linux uses TSC because we want high accuracy (nanosecond scale) without
>having slow stuff.

Please, don't confuse accuracy with precision.  The TSC is precise 
but not accurate.  The 100Hz timer is more accurate, especially given 
a SpeedStep CPU, but much less precise.  It's a subtle distinction, 
but an important one.

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