cx_lowest and CPU usage

[Nate Lawson]

Andriy Gapon wrote:
> Report for 7.0-RC1 on quite old hardware: 440BX-based motherboard,
> 450Mhz Pentium III (Katmai).
> 
> cx_supported claims to support C1, C2, C3. If I set cx_lowest to C3 it
> immediately gets backed out to C2 with a kernel message about too many
> short sleeps. But that's not a problem.
> There is a weird thing: if I change cx_lowest to C2 when the machine is
> completely idle, top shows that CPU usage for interrupts immediately
> jumps to almost 20%. Change cx_lowest to C1, CPU usage drops back to
> almost 0%.
> Is this normal ?
> If not, does this indicate some problem in idle routine or is this just
> incorrect statistics calculation ? Or maybe something with HW ?

Leave it at C1.  Apparently C2 and C3 don't work on your machine. 
That's understandable with older, non-laptop hw.

-- 
Nate