[2.5.73] What causes this high interrupt count?

[2.5.73] What causes this high interrupt count?

[Jurgen Kramer]

Hi,

With 2.5.73 with ACPI enabled on my P4 HT system irq 18 seems to be
very busy:
           CPU0       CPU1
  0:     633529      76869    IO-APIC-edge  timer
  2:          0          0          XT-PIC  cascade
  9:          0          0   IO-APIC-level  acpi
 14:      12139          0    IO-APIC-edge  ide0
 15:          2          0    IO-APIC-edge  ide1
 16:      58707          0   IO-APIC-level  uhci-hcd, uhci-hcd, nvidia
 17:      56840          0   IO-APIC-level  Intel ICH5
 18:   88494437   48181320   IO-APIC-level  ide2, uhci-hcd
 19:      15975          0   IO-APIC-level  uhci-hcd
 20:        183          0   IO-APIC-level  ohci1394
 21:       1647          0   IO-APIC-level  eth0
 23:         68          0   IO-APIC-level  ehci_hcd
NMI:          0          0
LOC:     710285     710628
ERR:          0
MIS:          0

ide2 is the onboard Intel SATA (ICH5) controller. I am not sure what is
causing these interrupts.

Top shows a lot of CPU load being generated caused by the high interrupt
count:

81 processes: 80 sleeping, 1 running, 0 zombie, 0 stopped
CPU0 states:   2.0% user  58.0% system    0.0% nice   0.0% iowait  40.0%
idle
CPU1 states:   3.0% user   0.0% system    0.0% nice   0.0% iowait  97.0%
idle
Mem:   515480k av,  198452k used,  317028k free,       0k shrd,   14760k
buff
       122252k active,              50596k inactive
Swap:  787176k av,       0k used,  787176k free                   94040k
cached

I've had the same problem with 2.4.21 plus a recent ACPI. What can be
the culprit?

Cheers,

Jurgen