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According to my powertop (on 5.3.1 kernel):

Power est.              Usage       Events/s    Category       Description
 ...
  3.85 W      7,7 ms/s     437,0        Timer          tick_sched_timer

3.85W on a Laptop is huge, sometimes it gets even up to 6W. I haven't seen this on earlier kernels (5.0.x), does anyone know how to reduce that power usage?

Krzysztof Krasoń
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2 Answers2

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tick_sched_timer is part of the linux kernel's cpu scheduler. In this case, it is likely indicating many context switches and cpu-wakeups on your system.

If you are seeing it using a lot of power, it's likely that something on your system is causing a lot of context switches and/or cpu-wakeups. -- This could be related to a driver; such as a gpu driver, bluetooth, wifi, etc. - where it has some kind of aggressive update interval, or possibly a driver is firing many hardware interrupts... However, it could also be caused by some userpsace software, as well... even powertop will skew these numbers a bit.

You may have some success by disabling drivers (like bluetooth), when not in use (or if unused, completely blacklisting them). or changing cpu governors and/or using various power-saving methods/strategies... Depending on how your kernel is configured, reducing the timer tick may also save power. For example, some kernels may be build with CONFIG_HZ_1000=y, while others may be built with CONFIG_HZ_250=y. the latter should save some power.

Powertop may give you indications as to what the cause is; but tick_sched_timer isn't the root cause of your battery drain (it's only a symptom). It's likely some other thread, task or process; in the kernel or possibly in user-space.

jrdnjhntsn
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0

A bit late to the party but I dropped by usage from average above 2W to less than 1 by adjusting my settings with tlpui.

Go to Processor and tick the SCHED_POWERSAVE options to on. You can also mess around with the many CPU adjustments in that category.

For Intel CPUs: go to Graphics and adjust the INTEL_GPU_FREQ to lower values, be sure to check what is available by using sudo tlp-stat -g beforehand.

For AMD CPUs: go to Graphics and set RADEON_POWER_PROFILE_ON_BAT and RADEON_DPM_STATE to low and battery, respectively.

Disabling bluetooth also seems to help.

Obviously this is not ideal as performance is lowered quite a bit, but if you value battery life more than performance then go with this.

Jeff Chen
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