Laptop power consumption (on battery)

[Hallvor]

I thought it would be interesting to compare watt usage and share tips on how to lower it.

Rules for comparison:

* Give hardware info.
* Distro and desktop environment/Wm.
* Notify of application used for power saving (TLP, CPUfreq, etc.).
* Have Wifi ON, Bluetooth OFF, Screen ON (but you can lower the brightness as long as it is readable).
* Use Powertop after clean boot with nothing else running. Wait a few minutes until the discharge rate stabilizes, and then post your readings from the "Overview" tab.

My info:
This is from my ThinkPad T440S in my signature. It has a touch screen, so I guess it draws a little extra power.
Debian Bullseye, KDE.
TLP (customized).

Code: Select all

The battery reports a discharge rate of 4.61 W
The power consumed was 92.4 J
The estimated remaining time is 14 hours, 23 minutes

Summary: 610,7* wakeups/second,  0,0 GPU ops/seconds, 0,0 VFS ops/sec and 6,4% CPU use

Power est.              Usage       Events/s    Category       Description
  575 mW      1,8 ms/s     146,9        Timer          tick_sched_timer
  502 mW      4,4 ms/s     127,6        Interrupt      [18] i801_smbus
  416 mW      9,9 ms/s     104,1        Process        [PID 439] [irq/47-rmi4_smb]
  323 mW      3,1 ms/s      82,1        Process        [PID 1541] /usr/bin/kwin_x11
  179 mW     16,4 ms/s      41,6        Process        [PID 4054] /usr/bin/konsole
  130 mW     12,6 ms/s      30,1        Process        [PID 1068] /usr/lib/xorg/Xorg -nolisten tcp -auth /var/run/sddm/{e439d26c-f760-4d55-8efb-e160274f09ba} -background none -norese
  108 mW      7,0 ms/s      25,9        Process        [PID 1528] /usr/bin/kwin_x11
 27.9 mW    114,8 µs/s       7,1        Process        [PID 13] [rcu_sched]
 26.9 mW     64,7 µs/s       6,9        kWork          psi_avgs_work
 15.2 mW     14,4 µs/s       3,9        kWork          kfree_rcu_monitor
 14.4 mW     34,5 µs/s       3,7        kWork          engine_retire
 14.2 mW     23,3 µs/s       3,6        kWork          kfree_rcu_work
 14.1 mW     93,3 µs/s       3,6        kWork          gc_worker
 11.1 mW      2,4 ms/s       2,2        kWork          intel_atomic_commit_work
 8.89 mW    148,3 µs/s       2,2        Interrupt      [46] i915
 8.79 mW     41,6 µs/s       2,2        kWork          intel_atomic_cleanup_work
 7.44 mW     53,2 µs/s       1,9        kWork          __intel_wakeref_put_work
 5.48 mW     37,3 µs/s       1,4        Process        [PID 42] [kcompactd0]
 3.90 mW     11,3 µs/s       1,0        kWork          pci_pme_list_scan
 3.86 mW    165,5 µs/s       0,9        Timer          hrtimer_wakeup
 3.71 mW     12,7 µs/s       0,9        Timer          watchdog_timer_fn
 3.49 mW    578,7 µs/s       0,7        Process        [PID 4078] powertop
 3.36 mW     60,6 µs/s       0,8        Process        [PID 426] [irq/50-iwlwifi]
 2.53 mW      3,3 µs/s       0,6        Timer          sched_rt_period_timer
 2.33 mW      1,7 ms/s      0,15        Interrupt      [7] sched(softirq)
 2.10 mW    155,7 µs/s       0,5        Process        [PID 631] /usr/sbin/NetworkManager --no-daemon
 1.78 mW     33,2 µs/s       0,4        Process        [PID 599] /usr/sbin/haveged --Foreground --verbose=1
 1.75 mW      4,7 µs/s       0,4        kWork          intel_atomic_helper_free_state_
 1.57 mW     10,7 µs/s       0,4        kWork          vmstat_shepherd
 1.43 mW     74,2 µs/s       0,3        Process        [PID 1524] /usr/bin/kded5
 1.17 mW      3,8 µs/s      0,30        kWork          handle_update
(and many more not included)

* I don't know what happened here, but it can go as low as about 31 a second.

[stevepusser]

Your particular CPU supports undervolting (not overclocking!) rather easily via iuvolt or many other tools (none of which are in Debian, though). This makes the machine use less power for a given amount of work done, and run cooler. It even allows my laptop to run faster on AC under maximum load, since it reduces heat and thus thermal throttling. You may add that to your list.

[Hallvor]

Nice. Will this work?

Code: Select all

git clone https://github.com/tiziw/iuvolt.git
cd iuvolt && sudo chmod +x install.sh
sudo ./install.sh

#Experiment with right values
sudo iuvolt -90 -80 -90

#Save values to config
vi /etc/iuvolt.cfg

https://github.com/tiziw/iuvolt

[stevepusser]

Nice. Will this work?

Code: Select all

git clone https://github.com/tiziw/iuvolt.git
cd iuvolt && sudo chmod +x install.sh
sudo ./install.sh

#Experiment with right values
sudo iuvolt -90 -80 -90

#Save values to config
vi /etc/iuvolt.cfg

https://github.com/tiziw/iuvolt

Yes,looks good, but you can use the same voltage undervolt values that other users may have already determined for your particular laptop on the Windows side for the Throttlestop application, saving yourself the trouble of determining those through trial and error. You'll just need some powerful google-fu, and using i7z and some CPU stressing (s-tui) and temperature monitoring widget or app helps determine if its helping. For my particular laptop with six cores, the maximum CPU speed under sustained 100% load and the discrete Nvidia GPU turned off went from 3.2 GHz to 3.6 GHz, which helps for package building like I'm about to do for multiple versions of Pale Moon 29.2.0...