Dell Latitude D820 laptop, T7200 Core2 Duo, x86_64 kernel built with PREEMPT, NO_HZ, and HZ=1000. It's running basically idle with an X desktop session.
I'm seeing large masses of rescheduling interrupts that are basically killing
the C3 residency rate for no obvious reason/gain. I'm taking close to 500
interrupts/second, of which close to 350 are unexplained and apparently
gratuitous. Anybody have suggestions/clues on how to find out why I'm seeing
this? (Quite possibly, I've got something misconfigured because I misunderstood
the documentation - which would still indicate that the doc needs fixing at the
least...)
powertop reports:
PowerTOP version 1.9 (C) 2007 Intel Corporation
Cn Avg residency P-states (frequencies)
C0 (cpu running) ( 5.6%) 2.00 Ghz 1.2%
C1 0.0ms ( 0.0%) 1.67 Ghz 0.0%
C2 0.7ms ( 5.1%) 1333 Mhz 0.0%
C3 2.1ms (89.3%) 1000 Mhz 98.8%
Wakeups-from-idle per second : 494.9 interval: 10.0s
no ACPI power usage estimate available
Top causes for wakeups:
43.9% (190.3) <kernel IPI> : Rescheduling interrupts
29.4% (127.4) <interrupt> : extra timer interrupt
5.9% ( 25.6) X : do_setitimer (it_real_fn)
5.0% ( 21.7) gkrellm : schedule_timeout (process_timeout)
3.9% ( 16.7) group_balance : schedule_timeout (process_timeout)
3.0% ( 13.2) <interrupt> : iwl3945
2.3% ( 10.0) <kernel core> : ehci_work (ehci_watchdog)
/proc/interrupts (after about 10 hours of uptime, most of which was mostly
idle and "fetchmail check the mail server every 5 minutes"):
CPU0 CPU1
0: 14507246 0 IO-APIC-edge timer
1: 10748 0 IO-APIC-edge i8042
8: 0 0 IO-APIC-edge rtc
9: 3 0 IO-APIC-fasteoi acpi
12: 86 0 IO-APIC-edge i8042
14: 147067 0 IO-APIC-edge ata_piix
15: 45 0 IO-APIC-edge ata_piix
16: 91584 0 IO-APIC-fasteoi nvidia
19: 9 0 IO-APIC-fasteoi ohci1394, yenta
20: 51139 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2
21: 34708 0 IO-APIC-fasteoi uhci_hcd:usb3, HDA Intel
22: 0 0 IO-APIC-fasteoi uhci_hcd:usb4
23: 0 0 IO-APIC-fasteoi uhci_hcd:usb5
312: 164320 0 PCI-MSI-edge eth0
313: 385582 0 PCI-MSI-edge iwl3945
314: 1343 0 none-edge
NMI: 0 0 Non-maskable interrupts
LOC: 1263420 5737965 Local timer interrupts
RES: 2285220 2305246 Rescheduling interrupts
CAL: 4068 6172 function call interrupts
TLB: 41441 44272 TLB shootdowns
TRM: 0 0 Thermal event interrupts
THR: 0 0 Threshold APIC interrupts
SPU: 0 0 Spurious interrupts
ERR: 0
Any ideas/hints?
pgpxV5kdOdGbl.pgp
Description: PGP signature
