Current battery life impact of Nvidia Prime Offloading driver

Hey Guys,

I have a question regarding the newly added Nvidia Prime Offloading.
When dGPU is not being used, what is the expected power consumption?
Is it like in the case of bumblebee - so no power is consumed? Or the gpu is on?

Depends on hardware(generation): for pre-turing generations it's considerably higher than before. Also see


and

Use powertop in terminal to check the energy usage. I'll be testing it myself since I'm also curious about the outcome.

Currently, I see 3 Nvidia processes:


 24.8 mW    405,2 µs/s       6,3        Process        [PID 3653] [irq/139-nvidia]
 3.49 mW    320,9 µs/s       0,8        Interrupt      [139] nvidia
 0 mW    100,0%                      Device         PCI Device: NVIDIA Corporation GM204M [GeForce GTX 970M]

Since I'm using optimus-manger I can switch between Intel, Nvidia and Hybrid mode. The above output is in the Hybrid mode. I'll update the info if I get more measurments.

EDIT:
Here are couple data.

  1. [irq/139-nvidia process:
29.8 mW 250,8 µs/s           11
24.8 mW 405,2 µs/s          6,3
16.4 mW    214,5 µs/s       4,2
 31.1 mW    375,7 µs/s       7,9
10.3 mW    147,4 µs/s       2,6
 10.3 mW    157,3 µs/s       2,6
 13.4 mW    203,2 µs/s       3,4
 8.93 mW    115,2 µs/s       2,3
12.8 mW    193,4 µs/s       3,2
8.23 mW     87,1 µs/s       2,1
26.2 mW    382,8 µs/s       6,6
 9.95 mW    143,5 µs/s       2,5
 9.76 mW    133,2 µs/s       2,5
 21.7 mW    334,2 µs/s       5,5
 26.8 mW    368,6 µs/s       6,8 
 29.0 mW    419,2 µs/s       7,3
7.28 mW     95,8 µs/s       1,8
  1. [139] nvidia interupt
7.07 mW 320,9 µs/s           2,5
3.49 mW 320,9 µs/s           0,8
 3.27 mW    345,2 µs/s       0,7
 6.54 mW    319,6 µs/s       1,6 
7.44 mW     81,4 µs/s       1,9
 1.50 mW    288,4 µs/s       0,3
4.18 mW    295,9 µs/s       1,0
10.4 mW    150,9 µs/s       2,6
2.81 mW    284,7 µs/s       0,6
 4.71 mW    272,2 µs/s       1,1
 9.39 mW    292,3 µs/s       2,3 
 2.69 mW    297,6 µs/s       0,6
 2.25 mW    291,1 µs/s       0,5 
 6.50 mW    284,3 µs/s       1,6 
 3.20 mW    265,6 µs/s       0,8
 9.79 mW    274,4 µs/s       2,4 
 3.38 mW    290,0 µs/s       0,8

Device is always shown as 0.

I wish there was a way to print powertop's data to a spreadsheet. I could do some calculations like averages and percentage of the total usage, etc. Without it, it's just too much work :frowning:.

Luckily, when running on battery, powertop shows a global consumption and battery estimated life. However, it still shows an estimate for the given measurment, not the average, so the data varies ca. between:


The battery reports a discharge rate of 28.6 W
The power consumed was 617 J
The estimated remaining time is 3 hours, 33 minutes

and

The battery reports a discharge rate of 25.3 W
The power consumed was 512 J
The estimated remaining time is 4 hours, 1 minutes

Sometimes it shows even over 5 hours, but mostly something about 3,5 hours +/-

In Nvidia mode I get battery life between 2:20 to 5:22.... Hard to get the real average estimate. I would say that probably around 3 hours, so less then on hybrid. Can't be sure thou because I don't have the real calculations, only observation.

In Intel mode it shows between 4 or 7 hours, usually around 5 hours!

So the quick conclusion is: PRIME Offloading setup uses 85% of the power that PRIME does. Stll, Intel offers a superior battery life over both PRIME setups (at least 33% better). That is why for hybrid GPUS it's so nice to have optimus-manger and not the static setup.

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A bit off-topic for @domi.nos but helpful for @michaldybczak

Tip: you can open any text file in LibreOffice Calc and it'll convert it to a spreadsheet.

  • Easiest is when the text file has its fields delimited by tabs.
  • You can also delimit the fields by a comma or semicolon (=CSV=Comma Separated Values)

:innocent:

I know, but I would have to put those commas or semicolons myself, because replacing space bars wouldn't do it because there is more of them. I guess with some combination I could make something useful out of it. However, the problem is, I can't mark all text from powertop's output (the option is grayed out) and I can't mark the whole text manually. I could do this one part by part but then output would change in the middle. This is impossible. Powertop is for looking but not meant to import the data, which is a shame. So no matter how to format the text to make spreadsheet out of it, getting that data from the terminal is a problem too.

cat and sed to the rescue:

cat FileWithSpaces.txt | sed 's/ \+/\t/g' 1> FileWithTabs.txt 2>FileWithTabs.err

This will:

  • cat: pipe the contents of FileWithSpaces.txt to sed (Stream EDitor)
  • which s earches (and replaces) +: one or more spaces by a single tab ( \t) g lobally (I.E.: the entire line)
  • and redirects the output (but not the errors) to FileWithTabs.txt
  • and the errors to FileWithTabs.err

For more info:

man sed

:innocent:

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Added to notes :slight_smile: . Thank you.

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Sorry for the late reply.
I kind of wonder, what do you mean by hybrid mode? I assume, that Intel and Nvidia is when only Intel is used, and when only Nvidia is used. But hybrid = bumblebee, or Prime offloading?

By hybrid mode I understand Prime Offloading. Optimus-manager allow you to switch between those 3 modes at wish: Intel, Hybrid, Nvidia.

Hybrid mode is rather more meant for a very modern hardware where it's more efficient. On some new computers Hybrid mode can power down Nvidia completely. However, on most laptops that are few year old and older, hybrid mode will consume only little less than Nvidia and a way more than Intel. Also, hybrid mode doesn't allow for multi-monitors, at least now. So it's very handy to be able to switch to Intel (power saving) or Nvdia (performance) mode when needed.

So to answer your question, prime offloading energy usage depends on very highly from the hardware and settings, so it can vary strongly and for most current laptops the power usage is still high, although a little better than on full Nvidia.

More info about hybrid mode and power management can be found here:

It appears, the easiest way of finding out was to test. On my particula machine, the difference is of around 1 Watt. So, I prefer bumblebee.

Thanks for all the replies :slight_smile:

Bumblebee doesn't support vulkan so if you want to use Proton, you need to switch to nvidia-xrun:

There is also xgraphic package that allows you for switching between standard bumblebee and nvidia setup. The package is in Manjaro repo. Additional instructions can be found here:

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