I use indicator-cpufreq with Cinnamon to control my CPU-usage and save power, as my battery life has been running low. So, I use indicator-cpufreq to put my CPU in powersave mode. However, I have this weird issue with Cinnamon, that sometimes when I wake up from suspend, CPU usage skyrockets up to 40% per core, and everything slows down significantly. This happened again with my CPU in powersave mode. However, when I tried putting it in performance mode, everything went back to normal speed, and the CPU usage fell back to normal. So my question is, what does it do to put my CPU in powersave mode? The usage of my CPU increased and everything slowed down, so is it even helping out at all? Is it even saving power?

On a side note, according to all the images I see of indicator-cpufreq, it gives multiple options to choose from, whereas I only see the options Performance and Powersave. Why is this?

  • 1
    Does the CPU stay pegged at 40%? Or are you just noticing it immediately upon resuming? – Bratchley Mar 8 '16 at 19:19
  • Probably what you are seeing is that the CPUs go to sleep, and a lot of work to do accumulates for when they wake up. – vonbrand Mar 8 '16 at 19:54
  • @vonbrand - But it stays like that. The first time this issue happened, I coped with it for a while, and it didn't get any better, so I had to fix it by putting my computer in suspend again, and waking it up again. – Rohan Mar 9 '16 at 0:48
  • You only see performance and powersave because you are on a system that uses intel P-State driver. – Runium Mar 10 '16 at 0:17
  • @Sukminder could you elaborate what it means to be on a system using the intel P-State driver? Your link is fairly cryptic to me. – Rohan Mar 13 '16 at 21:02

So my question is, what does it do to put my CPU in powersave mode?

It's adjusting the clock frequency/core activation so that it uses less power.

When you're on the performance governor, it's probably still performing the same work as before, it's just getting through it faster. If your system has fewer resources (such as because you switched governors) being at "40%" no longer means what it did when you were using all your cores at maximum clock frequency. You're at "40%" but it's likely because your overall capacity has shrunk as a result of trying to save power.

If you don't like what it picks by default there are tunables for controlling how fast it will react to increased load and how far it'll ramp up/down but that's a little too open ended to give you specific examples. You just have to see what works for you.

The usage of my CPU increased and everything slowed down, so is it even helping out at all?

The point of CPU governors being a tunable is that the admin (i.e you) is supposed to tell the system what "helping" actually means. In your case, putting it into powersave is you telling the system that you care more about battery life than you do about a fast system.

Is it even saving power?

You can make note of how much power is being consumed by the CPU's or just make general note of how fast your battery drains. It may be helping, you just have to check to see. The CPU isn't the only thing that consumes power (your display and peripherals can consume a lot as well) but the CPU is all the governor is going to control.

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