Increasing battery time by decreasing processor wakeups?

English Hardware
1

Hello dear members of the forums,

is it possible (and does it make sense) to make my laptop use less energy without a real standby allowing the processor (cpu) to ‘sleep’ a bit more between working?

It seems to me I have already got the processor a bit more resting time by following the hints of ‘powertop’ (that has to be run with superuser rights e. g. with sudo) and by installing laptop-tools.

 PowerTOP version 1.11      (C) 2007 Intel Corporation

Cn Avg residency P-states (frequencies)
C0 (cpu running) ( 2.1%) 1.74 Ghz 6.4%
C0 0.0ms ( 0.0%) 1333 Mhz 1.2%
C1 halt 0.0ms ( 0.0%) 1067 Mhz 0.0%
C2 48.7ms (50.2%) 800 Mhz 92.4%
C3 18.9ms (47.7%)

Wakeups-from-idle per second : 35.5 interval: 20.0s
no ACPI power usage estimate available

Top causes for wakeups:
23.1% ( 11.2) <kernel core> : hrtimer_start_range_ns (tick_sched_timer)
20.6% ( 10.0) <interrupt> : ipw2200, Intel ICH6 Modem
10.4% ( 5.0) <interrupt> : ata_piix
6.2% ( 3.0) scim-panel-gtk : hrtimer_start_range_ns (hrtimer_wakeup)
4.1% ( 2.0) multiload-apple : hrtimer_start_range_ns (hrtimer_wakeup)
3.6% ( 1.8) gnome-terminal : hrtimer_start_range_ns (hrtimer_wakeup)

Suggestion: increase the VM dirty writeback time from 5.00 to 15 seconds with:
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
This wakes the disk up less frequently for background VM activity
Q - Quit R - Refresh W - Increase Writeback time

 PowerTOP version 1.11      (C) 2007 Intel Corporation

Cn Avg residency P-states (frequencies)
C0 (cpu running) ( 2.0%) 1.74 Ghz 10.6%
C0 0.0ms ( 0.0%) 1333 Mhz 0.0%
C1 halt 0.0ms ( 0.0%) 1067 Mhz 0.1%
C2 45.3ms (46.5%) 800 Mhz 89.4%
C3 0.0ms ( 0.0%)
C4 20.0ms (51.5%)
Wakeups-from-idle per second : 35.9 interval: 15.0s
Power usage (ACPI estimate): 17.4W (4.4 hours) (long term: 11.7W,/6.5h)

Top causes for wakeups:
24.5% ( 11.5) <kernel core> : hrtimer_start_range_ns (tick_sched_timer)
22.1% ( 10.3) <interrupt> : ipw2200, Intel ICH6 Modem
10.0% ( 4.7) <interrupt> : ata_piix
4.3% ( 2.0) scim-panel-gtk : hrtimer_start_range_ns (hrtimer_wakeup)
4.3% ( 2.0) multiload-apple : hrtimer_start_range_ns (hrtimer_wakeup)
3.9% ( 1.8) <kernel core> : hrtimer_start (tick_sched_timer)

Suggestion: Disable ‘hal’ from polling your cdrom with:
hal-disable-polling --device /dev/cdrom ‘hal’ is the component that auto-opens a

Q - Quit R - Refresh K - kill hald-addon-storage

For example:

  • “hrtimer_start_range_ns (tick_sched_timer)” seems to be a hight precise timer program - what is it used for and may I reduce how often it is used?
  • “ipw2200, Intel ICH6 Modem” seems to wakeup my cpu just 10 times a second but I thought I had already set my wlan to ping only 1x per second - is this my (not at all used) modem?

Greetings
pistazienfresser

2

On 07/06/2010 08:56 AM, pistazienfresser wrote:
>
> Hello dear members of the forums,
>
> is it possible (and does it make sense) to make my laptop use less
> energy without a real standby allowing the processor (cpu) to ‘sleep’ a
> bit more between working?
>
> It seems to me I have already got the processor a bit more resting time
> by following the hints of ‘powertop’ (that has to be run with superuser
> rights e. g. with sudo) and by installing laptop-tools.
>
>>
>> PowerTOP version 1.11 (C) 2007 Intel Corporation
>>
>> Cn Avg residency P-states
>> (frequencies)
>> C0 (cpu running) ( 2.1%) 1.74 Ghz 6.4%
>> C0 0.0ms ( 0.0%) 1333 Mhz 1.2%
>> C1 halt 0.0ms ( 0.0%) 1067 Mhz
>> 0.0%
>> C2 48.7ms (50.2%)
>> 800 Mhz 92.4%
>> C3 18.9ms (47.7%)
>>
>> Wakeups-from-idle per second : 35.5 interval: 20.0s
>> no ACPI power usage estimate available
>>
>> Top causes for wakeups:
>> 23.1% ( 11.2)<kernel core> : hrtimer_start_range_ns
>> (tick_sched_timer)
>> 20.6% ( 10.0)<interrupt> : ipw2200, Intel ICH6 Modem
>> 10.4% ( 5.0)<interrupt> : ata_piix
>> 6.2% ( 3.0) scim-panel-gtk : hrtimer_start_range_ns
>> (hrtimer_wakeup)
>> 4.1% ( 2.0) multiload-apple : hrtimer_start_range_ns
>> (hrtimer_wakeup)
>> 3.6% ( 1.8) gnome-terminal : hrtimer_start_range_ns
>> (hrtimer_wakeup)
>>
>> Suggestion: increase the VM dirty writeback time from 5.00 to 15
>> seconds with:
>> echo 1500> /proc/sys/vm/dirty_writeback_centisecs
>> This wakes the disk up less frequently for background VM activity
>> Q - Quit R - Refresh W - Increase Writeback time
>>>
>> PowerTOP version 1.11 (C) 2007 Intel Corporation
>>
>> Cn Avg residency P-states (frequencies)
>> C0 (cpu running) ( 2.0%) 1.74 Ghz 10.6%
>> C0 0.0ms ( 0.0%) 1333 Mhz 0.0%
>> C1 halt 0.0ms ( 0.0%) 1067 Mhz 0.1%
>> C2 45.3ms (46.5%) 800 Mhz 89.4%
>> C3 0.0ms ( 0.0%)
>> C4 20.0ms (51.5%)
>> Wakeups-from-idle per second : 35.9 interval: 15.0s
>> Power usage (ACPI estimate): 17.4W (4.4 hours) (long term: 11.7W,/6.5h)
>>
>> Top causes for wakeups:
>> 24.5% ( 11.5)<kernel core> : hrtimer_start_range_ns
>> (tick_sched_timer)
>> 22.1% ( 10.3)<interrupt> : ipw2200, Intel ICH6 Modem
>> 10.0% ( 4.7)<interrupt> : ata_piix
>> 4.3% ( 2.0) scim-panel-gtk : hrtimer_start_range_ns
>> (hrtimer_wakeup)
>> 4.3% ( 2.0) multiload-apple : hrtimer_start_range_ns
>> (hrtimer_wakeup)
>> 3.9% ( 1.8)<kernel core> : hrtimer_start (tick_sched_timer)
>>
>> Suggestion: Disable ‘hal’ from polling your cdrom with:
>> hal-disable-polling --device /dev/cdrom ‘hal’ is the component that
>> auto-opens a
>>
>> Q - Quit R - Refresh K - kill hald-addon-storage
>>
>> For example:
> - “hrtimer_start_range_ns (tick_sched_timer)” seems to be a hight
> precise timer program - what is it used for and may I reduce how often
> it is used?
> - “ipw2200, Intel ICH6 Modem” seems to wakeup my cpu just 10 times a
> second but I thought I had already set my wlan to ping only 1x per
> second - is this my (not at all used) modem?

ipw2200 is an 802.11g wireless device, not a dial-up modem.

3

That is what I have thought, too.

LessWatts.org - Saving Power on Intel systems with Linux
I already entered

iwpriv eth0 set_power 5

in the GNOME terminal as root (after su -)
but this seems to make no difference to the
frequency of
"<interrupt> : ipw2200, Intel ICH6 Modem ".

Any idea(s)?

Greetings
pistazienfresser

4

On 07/06/2010 04:16 PM, pistazienfresser wrote:
>
> Code:
> --------------------
> iwpriv eth0 set_power 5
> --------------------
> in the GNOME terminal as root (after su -)
> but this seems to make no difference to the
> frequency of
> "<interrupt> : ipw2200, Intel ICH6 Modem ".

Changing the wifi power will not change the frequency of any timer loops
that the driver is running. If you want to cut the frequency, you would
have to find that timer loop and change its frequency, but you would then
run the risk of breaking the device. If you really want to save power,
don’t use the device and unload the driver.

5

Thanks for your answers.

Do you think the linked Intel page is out of date?
I would rate it also possible that I have done something wrong/unusual in the configuration of my wireless lan (WLAN) in the first place - :.
But the NetworkManager (or its applet) tells me:
“Interface: 802.11 WiFi (eth0)
…]
Driver: ipw2200”

Thanks, but if this is really the wireless lan adapter - I use it.

Any idea to reduce the other wakeups/interrups?

Good night/greetings
pistazienfresser