Managing Clock Speed on Android Devices

[mjslakeridge]

Hopefully this is the correct section of the forum for my question. I have 2 Android devices, a Samsung tablet and an LG Leon Smartphone. I have installed CPU-Z on both devices. When the Samsung tablet is in nearly idle mode the clock speed of CPU 0 drops to 300 MHz and CPU 1-3 are parked, presumably to save battery power.

However on the LG Phone, the lowest clock speed is 800 MHz, on all four cores.

Both have the exact same Android Version 5.1.1. According to CPU-Z the clock speed range for the Samsung is 300 MHz - 1.19 GHZ. For the LG Leon it is 200 MHz - 1.21 GHz.

So my question is this: Is there a way to get into the operating system to make the LG Leon park some of the cores when the CPU load is very low, or to make the clock speed drop down to 200 MHz. Or are Android OS's "locked" to prevent people from screwing things up. If I can change the clock speed would this have a material difference on the power consumption?

 

[Rishabh Tatiraju]

Android OS is based on the Linux kernel. Like all other Linux-based operating system, Android disallows access to system modifications unless you are working with elevated privileges. Linux distributions provide a "root" account to accomplish the same. Users with root access are also called superusers.

Being based on the Linux kernel, Android OS is bound to have the feature. However, looking at the remote possibility that a regular user with no advance knowledge can stumble upon critical system settings and modify them to make the system unusable, the developers of Android have hidden this root access away from normal user's eyes.

All that being said, lets answer your questions -

1. Is there a way to get into the operating system to make the LG Leon park some of the cores when the CPU load is very low, or to make the clock speed drop down to 200 MHz, or are Android OS's "locked" to prevent people from screwing things up?

It is possible, but it will require you to root your device. Rooting is the process in which a normal user can access system specific features such as changing CPU settings, modifying kernel code, etc. It sure may seem dangerous in the hands of a normal user, but is a boon to developers and power users.

Rooting involves unlocking your bootloader. In computing, the bootloader is the first program that runs in a machine during its power on phase. It holds codes to boot a specific system partition, and in the case of mobiles, booting the mobile operating system. The moment you unlock your bootloader, your warranty is void, since you are tampering with the mobile.

After that, with the help of a custom recovery, you install an app in your phone which basically manages the root access requests of other apps installed in your phone. This app is called the superuser app. Then, by using a Kernel tweaking app, you can modify the CPU settings. Of course this depends on whether your kernel has these features defined in its code and if your CPU has the frequency defined in its clock frequency range.

2. If I can change the clock speed would this have a material difference on the power consumption?

Yes. Lower clock frequency will result in lesser power consumption, and hence lower battery consumption. For example, I clock my phone's maximum CPU frequency down to 1.2 GHz instead of its default 1.6 GHz to save battery.

You might ask, "What should I do next?".

Firstly, head to XDA Developers forums and find your devices. Over there, you get plenty of guides to root your device. Then you can go get a kernel management software like Kernel Adiutor or Trickster Mod and change CPU frequencies, and if the kernel allows it, you can overclock or underclock your CPU.

 

[mjslakeridge]

Thanks for the detailed reply Rishabh. You confirmed in very elegant terms what I was suspecting. Fooling around with the advanced settings of the Android OS is not for a relative novice like me. I am sure with enough study I could attempt to modify the clock settings, but more than likely I would simply brick my 2 week old phone.

I just wish LG would have set it up differently so that some of the cores park when not needed. Even with WIFI and Bluetooth off, the battery seems to discharge faster than I would have imagined. Of course I am comparing my experience with my previous 7 year old non-smartphone which I only had to charge once a week or so (I don't make or receive many calls since I am usually at my computer and communicate via IM).

Again, Thank You.

 

[Rishabh Tatiraju]

Thanks for the detailed reply Rishabh. You confirmed in very elegant terms what I was suspecting. Fooling around with the advanced settings of the Android OS is not for a relative novice like me. I am sure with enough study I could attempt to modify the clock settings, but more than likely I would simply brick my 2 week old phone.

I just wish LG would have set it up differently so that some of the cores park when not needed. Even with WIFI and Bluetooth off, the battery seems to discharge faster than I would have imagined. Of course I am comparing my experience with my previous 7 year old non-smartphone which I only had to charge once a week or so (I don't make or receive many calls since I am usually at my computer and communicate via IM).

Again, Thank You.

No problems. Since the device is new, you can wait and see if an LG update fixes the issue, or go ahead with tweaking.

If you ever decide to go ahead and tweak your device, here is the link to your device forum at XDA Developers:
http://forum.xda-developers.com/t/lg-leon

 

[mjslakeridge]

I think I will limit my tweaking to PC BIOS settings, AMD Overdrive, etc. I have come close to screwing up several PCs over the years, but always was able to recover by resetting CMOS, having a cloned OS on a spare HDD, etc. I have only fooled around with LINUX once or twice, when I couldn't get a PC to boot from Windows, so by no means am I even close to being proficient.

I will bookmark the link you provided, just in case I want to learn more in the future.

 

[Rishabh Tatiraju]

I think I will limit my tweaking to PC BIOS settings, AMD Overdrive, etc. I have come close to screwing up several PCs over the years, but always was able to recover by resetting CMOS, having a cloned OS on a spare HDD, etc. I have only fooled around with LINUX once or twice, when I couldn't get a PC to boot from Windows, so by no means am I even close to being proficient.

I will bookmark the link you provided, just in case I want to learn more in the future.

Great! Hoping you have a great experience with Android!