Tick_sched_timer and power consumption

tick_sched_timer is by far the “process” at the top of powertop which consumes most energy. At those occasions when I have checked the energy consumption could be anything between 2.5 to 5 W. Is this normal? Are there any optimal settings/configuration to reduce it’s power consumption? I have tried to search and come up with some info that it is related to CPU wake-ups but not much beyond that. This is what I have have under WakeUp tab in powertop:

PowerTOP 2.13     Overview   Idle stats   Frequency stats   Device stats   Tunables   WakeUp                            

>> Enabled       Wake-on-lan status for device enp1s0                                                                   
   Disabled      Wake-on-lan status for device wlan0
   Disabled      Wake status for USB device 1-7
   Disabled      Wake status for USB device usb1
   Disabled      Wake status for USB device usb2

2.5 to 5 W is indeed a lot. Is that in idle?
In idle I have between 700 and 900 mW.

Which timer frequency does your kernel use? Arch vanilla has 300 Hz, but some desktop/gaming oriented kernels might have 1000 Hz.
(zgrep CONFIG_HZ /proc/config.gz)

You could use perf to get a little more info, e.g. run
sudo perf stat -a -d -- sleep 5


Hi, thanks for the reply!

No, I am afraid not. At the time of the running of powertop, the laptop was on battery, with both bluetooth and wifi on, with Firefox and at most 8-10 open tabs.

zgrep CONFIG_HZ /proc/config.gz

CONFIG_HZ_100 is not set
CONFIG_HZ_250 is not set
CONFIG_HZ_300 is not set

This is on:

uname -r


Now I did some casual measuring of tick_sched_timer’s power consumption, on battery, WiFi ON, Bluetooth OFF, no peripherals attached, only a terminal running powertop.

Based on ten consecutive readings, the power consumption of tick_sched_timer averaged at 370.6 mW with 217.3 wakeups/s

How does it look to you?

Oops, forgot about this :blush: I’ll get back with the result later.

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Difficult to say, I’m not an expert :wink:
Now I have about 1W, though with a 300 Hz kernel, browser, text editor, file manager, two terminals, WiFi. And typing this message.

If power saving is critical to you, don’t run a 1000 Hz kernel, AFAIK they always tend to use a little more power.

The perf command is not necessary, it just shows you some basic stats, like total CPU cycles, CPU migrations, cache hits & misses, and context switches.

The thing is that sadly enough the battery on this laptop deteriorated quite rapidly just within a couple of months after the purchase. So whenever it is on battery, I am on my toes. I’ll take your advice and switch to the normal linux kernel and see if I get better battery life.

I have been here for a short time. But what I have seen from your input, the above is an exaggerated understatement.

Thanks for helping out!