Am Donnerstag, den 04.02.2010, 12:30 +0100 schrieb Adam Sloboda:
> Hi all,
>
> In the past week I've been searching for the source of "<kernel IPI> :
> Rescheduling interrupts" -- I have more than 500 wakeups on idle
> system (ThinkPad X200).
>
> Today I tried to set affinity of processes to one core and then
> affinity of X process to the other one:
>
> for pid in `ps aux | awk '{print $2}'`; do taskset -c -p 0 $pid; done
>
> taskset -c -p 1 `pidof X`
>
> # You can restore it back (on dual-core):
> #for pid in `ps aux | awk '{print $2}'`; do taskset -c -p 0,1 $pid; done
>
> First command reduced Rescheduling interrupts rapidly and the second
> one caused it skyrocket back to hundreds. I noticed this with 2.6.30
> kernel but have no idea when this started. I'm now on 2.6.32.7, I
> tried minimal kernel config but no luck. I'm pretty sure this is not
> happening on 2.6.26 distribution kernel (Debian squeeze).
>
> I'm also getting a lot of "extra timer interrupt" wakeups (over 100)
> and a little less if all processes run on the same core. This might
> be also connected with the issue. So I still have pretty poor
> residency in sleep state but it's better.
>
> So it seems it's not any hardware driver but userspace process
> interaction (or X processes). This is dead end for me. As the
> result, I have 12-13 W power consumption on 12.1" centrino 2 laptop
> (Vista can get it down to somewhere around 6 when idle and disk turned
> off, wifi on).
>
> I will appreciate any ideas.
>
> Regards,
> Adam
I'm not 100% sure but your laptop get 8wh minimal. Please not post some
thing like "Vista can get 6W" haw did you get this info?
4-cell battery, 29 Wh (14.4 V, 2.0 Ah). up to 3.3 hr
29 / 3.3 = 8,48W
Wifi is about 1-2W, hdd 0.5W, 1-2W display.
IPI bug is know. The count of IPI wakeups increase with count of CPU
usage.
here is my dump with used system (ubuntu 9.10) and kernel
2.6.32-04066-g2b876f9-dirty. Here you can see IPI is not the problem.
Cn Avg residency
C0 (cpu running) ( 4.4%)
C0 0.0ms ( 0.0%)
C1 mwait 0.0ms ( 0.0%)
C2 mwait 0.3ms ( 0.1%)
C4 mwait 3.6ms (95.5%)
P-states (frequencies)
1.67 Ghz 1.3%
1333 Mhz 0.0%
1000 Mhz 98.7%
Wakeups-from-idle per second : 269.4 interval: 15.0s
Power usage (ACPI estimate): 10.2W (5.3 hours)
Top causes for wakeups:
23.0% ( 49.2) <kernel core> : hrtimer_start_range_ns
(tick_sched_timer)
17.4% ( 37.3) <interrupt> : extra timer interrupt
13.6% ( 29.1) firefox : hrtimer_start_range_ns
(hrtimer_wakeup)
7.0% ( 15.0) <interrupt> : ehci_hcd:usb1, uhci_hcd:usb2
6.5% ( 13.9) skype : hrtimer_start_range_ns
(hrtimer_wakeup)
6.5% ( 13.9) USB device 1-1 : HUAWEI Mobile (HUAWEI Technology)
5.8% ( 12.4) <kernel IPI> : Rescheduling interrupts
4.6% ( 9.9) desktopcouch-se : hrtimer_start_range_ns
(hrtimer_wakeup)
2.8% ( 6.0) <kernel core> : hrtimer_start (tick_sched_timer)
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