ACPI and interrupt storm--7.0 and 6.2

[John B]

Hope this is the right place to post this...please correct me if this  
is not the case.

I'm building 7.0 BETA3 (though same problem appears in 6.2-STABLE) on  
2- and 4-CPU Xeon boxes. Generic SMP and custom kernel configs build  
fine and all CPUs launch on reboot.

However, I get a lot of interrupts from ACPI. Load only settles down  
to around 0.4 at complete idle with almost no services running. If I  
turn off ACPI, obviously the interrupt 'storm' ceases, but then I  
lose the multiple CPUs.

I don't have access to the machine(s) at the moment, but my  
recollection is around 75000 ACPI interrupts per second (per vmstat -i).

Any suggestions? pointers? would be much appreciated.

Thanks
John