Kernels & CM10

[genebean]

I was wondering if anyone would be willing to share some opinions about why I might want to run a kernel other than the baked in one. I am looking for tangible reasons that I could verify if I ran the same kernel. Thanks!

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[cupfulloflol]

I was wondering if anyone would be willing to share some opinions about why I might want to run a kernel other than the baked in one. I am looking for tangible reasons that I could verify if I ran the same kernel. Thanks!

Sent from my Galaxy Nexus using Tapatalk 2

Different options that may not be present on their stock kernel. I haven't ran CM10's kernel, so I am going to just list some examples of what it could be lacking. If any of these matter to you that is a different story:
Overclocking and underclocking slots - There are kernels that ramp up to 1.8GHz (probably higher) and as low as 180MHz if your device can handle it, or if you were inclined to do so.

GPU options - Overclocking the GPU is possible too.

Governors - Either new governors or tweaked versions of old governors exist.

Schedulers - New or tweaked schedulers

Color calibration - I would assume CM10 does have this, but there are many options like say Trinity's contrast options which I would assume it is lacking.

Sound options - High performance sound and volume tweaks plus some others.

USB Fast charge - This allows your device to charge faster when connected to something like a USB port on a PC, but also can work on other places too. This does disable the ability for your device to communicate with the PC while on, but it is able to be toggled.

Smart Reflex - SR automatically undervolts your chipsets, making it unnecessary for you to do so manually.

Updates - Quite a few of the custom kernels are updated fairly regularly, almost daily. Adding features, fixing bugs, adding patches....etc

Battery life and performance- Theoretically some of these options can improve your battery life and performance. Different kernels and settings work a little differently for different setups and devices, so this would require experimentation to figure out which specific kernel and settings work best for you.

And probably many other things that I have neglected to mention.

For the most part though, you will probably be fine on stock. If you are happy, your device achieves what you need/want it to, while getting decent battery life and decent performance, then perhaps going to a custom kernel isn't necessary.

 

[genebean]

First off, thank you very much! I do have a couple of questions:

Governors - Either new governors or tweaked versions of old governors exist.

Can you explain what the governors do.

Schedulers - New or tweaked schedulers

Also, what do these do?


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[cupfulloflol]

Governors essentially are what tells your CPU what frequency (speed) it should be at times. Should it try and stay at the higher speeds, to be more responsive. Or should it stay at the lower end to preserve battery? Or should it be somewhere in the middle? This is super general, and I can provide a more technical explanation, or find a decent write up for further reading.

Android CPU governors explained - Android Forums <-- that generally explains some of the ones you may see. I haven't read them all, but it looks to be a decent writeup, and being that it is for a different phone so these governors could be different for our phone. Also remember any kernel dev can tweak these, so Interactive on one kernel may be slightly different than Interactive on another kernel. Also some devs have created new governors, or just modified existing ones and renamed them to avoid confusion. most probably has an explanation of their governors included somewhere.

Side note: It is possible that some governors may not be entirely stable. Hotplug for example can cause problems for some folks.

I/O scheduler is for the internal memory, it decides what order to do things on the hard disk. Theoretically speeding things up in certain situations or usage patterns. More in depth reading ( I/O scheduling - Wikipedia, the free encyclopedia ) . Note that some schedulers may not be 100% stable, or very useful for flash memory. Some are geared for mechanical hard drives, to decrease their seek times. You may not notice a big difference in these. These probably won't impact your battery life, at least theoretically they won't.

[REF] Governors and I/O schedulers - xda-developers <-- once again not for the GN, but gives another rough idea about governors, but more importantly schedulers in post 2.

 

[genebean]

... (Lots of good stuff)...

Thank you, this was very helpful.

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