CentOS 6 : Tip for significantly increasing battery life / reducing power consumption (Thinkpad X220 Tablet)
Hello,
I was not happy with the power consumption of CentOS 6 x86_64 on a new Lenovo Thinkpad x220 Tablet and I worked on reducing it. I just wanted to share with the list one of the changes which gave me the most significant improvement.
As per http://www.williambrownstreet.net/blog/?p=387, add the following kernel arguments to the GRUB boot configuration:
pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1
(in /boot/efi/EFI/redhat/grub.conf since I use EFI, /boot/grub/grub.conf otherwise)
As measured using PowerTop, this made the power consumption decrease from 20W to 11W ! (I had already decreased it from 25W to 20W with the usual tips of disabling hardware, shutting down services, switching tuned profiles, etc.)
All in all, battery time was more than multiplied by two, and the computer is now much more silent since the fan is not always running like mad in order to cool the processor. The bottom of the laptop is not anymore hot as hell.
I don't know whether this would have an impact on other hardware, but it may be worth looking at it (even on servers?), since the above link points to descriptions of a regression in the kernel which seems more general.
As a side note, the Power Management Guide of Red Hat is a good resource (analysis tools + tuned profiles): http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html-single/Pow...
Cheers,
Mathieu
PS: Do you think I should book a bug in the upstream bug tracker?
On Fri, Aug 3, 2012 at 3:05 PM, Mathieu Baudier mbaudier@argeo.org wrote:
pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1
Interesting as now I'm using RHEL 6.3 on T400. Would that make the notebook slower?
pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1
Interesting as now I'm using RHEL 6.3 on T400. Would that make the notebook slower?
I did not notice any change in performance so far. (Tested with parallelized, offline, Java build and unit tests)
On 03/08/12 08:05, Mathieu Baudier wrote:
Hello,
I was not happy with the power consumption of CentOS 6 x86_64 on a new Lenovo Thinkpad x220 Tablet and I worked on reducing it. I just wanted to share with the list one of the changes which gave me the most significant improvement.
As per http://www.williambrownstreet.net/blog/?p=387, add the following kernel arguments to the GRUB boot configuration:
pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1
(in /boot/efi/EFI/redhat/grub.conf since I use EFI, /boot/grub/grub.conf otherwise)
As measured using PowerTop, this made the power consumption decrease from 20W to 11W ! (I had already decreased it from 25W to 20W with the usual tips of disabling hardware, shutting down services, switching tuned profiles, etc.)
All in all, battery time was more than multiplied by two, and the computer is now much more silent since the fan is not always running like mad in order to cool the processor. The bottom of the laptop is not anymore hot as hell.
I don't know whether this would have an impact on other hardware, but it may be worth looking at it (even on servers?), since the above link points to descriptions of a regression in the kernel which seems more general.
As a side note, the Power Management Guide of Red Hat is a good resource (analysis tools + tuned profiles): http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html-single/Pow...
Cheers,
Mathieu
PS: Do you think I should book a bug in the upstream bug tracker?
Rather than filing a bug upstream, I would think it more appropriate to document the various settings on the CentOS Wiki in the laptops section:
----- Original Message ----- | Hello, | | I was not happy with the power consumption of CentOS 6 x86_64 on a | new | Lenovo Thinkpad x220 Tablet and I worked on reducing it. I just | wanted | to share with the list one of the changes which gave me the most | significant improvement. | | As per http://www.williambrownstreet.net/blog/?p=387, add the | following kernel arguments to the GRUB boot configuration: | | pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 | i915.i915_enable_fbc=1 | | (in /boot/efi/EFI/redhat/grub.conf since I use EFI, | /boot/grub/grub.conf otherwise) | | As measured using PowerTop, this made the power consumption decrease | from 20W to 11W ! | (I had already decreased it from 25W to 20W with the usual tips of | disabling hardware, shutting down services, switching tuned profiles, | etc.) | | All in all, battery time was more than multiplied by two, and the | computer is now much more silent since the fan is not always running | like mad in order to cool the processor. The bottom of the laptop is | not anymore hot as hell. | | I don't know whether this would have an impact on other hardware, but | it may be worth looking at it (even on servers?), since the above | link | points to descriptions of a regression in the kernel which seems more | general. | | As a side note, the Power Management Guide of Red Hat is a good | resource (analysis tools + tuned profiles): | http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html-single/Pow... | | Cheers, | | Mathieu | | PS: Do you think I should book a bug in the upstream bug tracker? | _______________________________________________ | CentOS mailing list | CentOS@centos.org | http://lists.centos.org/mailman/listinfo/centos |
You could also consider just sticking to tuned and then having a look at the power management options as provided there. tuned-adm list will show you some predefined power management options which *can* be tweaked.
Do you know what those options due to your machine in order to make the battery last longer? I mean really, do you know what they do?
These could be bad options for a number of users and since it's set at kernel boot time how can you override it once the OS has booted? Can you disable this without altering boot parameters and rebooting? If the answer is yes than a tuned configuration should be created or altered to set them dynamically. Setting of these at boot time are likely just wrong. You likely only want these to be turned on when the laptop is not attached to power, which you can create hooks for.
This is not a bug, it's a feature/workaround on specific hardware, that tweaks specific settings to get around a specific issue with the driver. Create a profile and submit it upstream.
You could also consider just sticking to tuned and then having a look at the power management options as provided there. tuned-adm list will show you some predefined power management options which *can* be tweaked.
I have made many tests with tuned and written small scripts to switch from one profile to the other (laptop-battery-powersave on battery, default on AC). Gains where in the 1W to 2W range vs. 9W gain with the kernel arguments (which is nice now that I'm around 12W, but it was 25W at the beginning!)
Do you know what those options due to your machine in order to make the battery last longer? I mean really, do you know what they do?
They are related to Intel graphic drivers (follow links in OP): http://www.williambrownstreet.net/blog/?p=387 http://askubuntu.com/questions/38117/battery-life-decreased-after-upgrade-to...
I don't know much more, but what I know is that this single change increased battery life on my laptop by a factor of two, that the fan is not running at full speed all the time (it also was on AC), and that nothing was broken for the last two days I have been working with it.
These could be bad options for a number of users and since it's set at kernel boot time how can you override it once the OS has booted? Can you disable this without altering boot parameters and rebooting? If the answer is yes than a tuned configuration should be created or altered to set them dynamically. Setting of these at boot time are likely just wrong. You likely only want these to be turned on when the laptop is not attached to power, which you can create hooks for.
Definitely, these could be bad options for some users (or, more likely, irrelevant ones). I posted to the list, so that when somebody will search for 'centos 6 thinkpad power consumption too high' he will bump into the Ubuntu related post I linked to (which provides additional links to the root cause) but also that this person will see that it worked pretty well in my particular case.
This is not a bug, it's a feature/workaround on specific hardware, that tweaks specific settings to get around a specific issue with the driver. Create a profile and submit it upstream.
The above links rather point to a regression.
I assume that CentOS users are experienced enough to do their own risks/benefits analysis before applying such tweaks. We can probably agree that we disagree on that point.
These could be bad options for a number of users and since it's set at kernel boot time how can you override it once the OS has booted? Can you disable this without altering boot parameters and rebooting? If the answer is yes than a tuned configuration should be created or altered to set them dynamically. Setting of these at boot time are likely just wrong. You likely only want these to be turned on when the laptop is not attached to power, which you can create hooks for.
Definitely, these could be bad options for some users (or, more likely, irrelevant ones). I posted to the list, so that when somebody will search for 'centos 6 thinkpad power consumption too high' he will bump into the Ubuntu related post I linked to (which provides additional links to the root cause) but also that this person will see that it worked pretty well in my particular case.
Just a quick note to say that I'm indeed experiencing stability issues. The X server sometimes freezes and I have to reboot. Also Firefox crashes more often than not.
I'm slowly trying to find out if this is due to these kernel arguments or to the combination with Compiz and docking etc. I'll post it here, if I gather more information.
As James pointed out, caution is required before applying these kernel arguments.
On 03/08/12 17:05, Mathieu Baudier wrote:
As per http://www.williambrownstreet.net/blog/?p=387, add the following kernel arguments to the GRUB boot configuration:
pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1
As measured using PowerTop, this made the power consumption decrease from 20W to 11W ! (I had already decreased it from 25W to 20W with the usual tips of disabling hardware, shutting down services, switching tuned profiles, etc.)
Thanks for the tips. I've got a X220 and power consumption is typically less than 10W, with various powertop tweaks on Fedora 17, giving me 8-9hrs of battery life.
The biggest win was setting i915.i915_enable_rc6=1 on the kernel command line, although I've read that this can cause some instability, depending on you kernel and usage -- had a couple of crashes/freezes a 6 months ago, but it seems pretty stable now. The benefits for a laptop definitely out-weigh the inconvenience or a few rare freezes, but it would be different for a server.
Might try out the other kernel line options and see if I can do better :-)
Here's my /etc/rc.d/rc.local file in case you are interested: ------------------------------------- #!/bin/bash
echo 5 > /proc/sys/vm/laptop_mode echo 0 > /proc/sys/kernel/nmi_watchdog echo 1 > /sys/devices/system/cpu/sched_mc_power_savings echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor echo 1500 > /proc/sys/vm/dirty_writeback_centisecs for i in /sys/bus/usb/devices/*/power/autosuspend; do echo 1 > $i; done for i in /sys/bus/usb/devices/*/power/level; do echo auto > $i; done echo min_power > /sys/class/scsi_host/host0/link_power_management_policy echo min_power > /sys/class/scsi_host/host1/link_power_management_policy echo Y > /sys/module/snd_hda_intel/parameters/power_save_controller echo 1 > /sys/module/snd_hda_intel/parameters/power_save for i in /sys/bus/{pci,i2c}/devices/*/power/control; do echo auto > $i; done
iwconfig wlan0 power on -------------------------------------
Cheers,
Kal
I was not happy with the power consumption of CentOS 6 x86_64 on a new Lenovo Thinkpad x220 Tablet and I worked on reducing it. I just wanted to share with the list one of the changes which gave me the most significant improvement.
As per http://www.williambrownstreet.net/blog/?p=387, add the following kernel arguments to the GRUB boot configuration:
pcie_aspm=force i915.i915_enable_rc6=1 i915.lvds_downclock=1 i915.i915_enable_fbc=1
As a follow-up: since the update to 6.4, these kernel arguments are *no longer required* in order to have a reasonable power consumption on a Thinkpad X220.
With tuned profile 'laptop-battery-powersave', the idle laptop consumes a bit more than 10W (with display turned of: 8W)
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