Abyss Kernel Tweaking Guide (ICS Kernel for SGS2)

I've been on Abyss Kernel for the past week (at least, back when I prepared this post) and I'm really impressed with its stability, battery life, and performance. In this post, I will teach you how to tweak your device settings using Abyss Kernel. I'm only going to cover what I believe are its most important tweaks for battery and performance.

Version reviewed in this post: Abyss Kernel v1.2 (latest)
Build date: May 18, 2012
Compatibility: Samsung, MIUI, AOSP, and AOKP ROMs
Developer: angelom
Download link: See List of SGS2 Kernels (ICS)

Features

• Abyss CWM Recovery
• Set screen brightness to lowest possible level (lower than stock Samsung firmware)
• Adjust voltage of CPU
• Change GPU frequencies
• Change value of charge current
• Adjust touch sensitivity
• Adjust gamma levels

Whoaaah. Let's slow down for a bit.

How to adjust screen brightness

Now the screen brightness, you can adjust directly on your phone. Just press and hold on the Status Bar and slide your finger across. There you go!

How to adjust CPU speed

NOTE: Underclock and overclock is possible.

You can also adjust the CPU speed using AnTuTu CPU Master Free or SetCPU available at Google Play. The CPU can be set from 200 to 1600 MHz (1.6 GHz) using either of these apps. These apps also allow you to select kernel governors like "ondemand," "performance," and "powersave". Basically, they are presets for CPU clockspeed. Each preset can affect the performance of your SGS2 as well as its battery life. To find out more about these Governor Tweaks, please refer to this amazing thread on XDA. Don't read too much though. It's going to give you a headache if you're an average user like me :)

One thing you may notice different is the "abyssplug" governor. This is a unique hotplug governor to Abyss Kernel. More about hotplug when you read along.

Abyss Kernel Tweaks

The Abyss Kernel has its own touch-based CWM Recovery. It has the functionality of CWM Recovery and more. With it, you can access the following under "ABYSS Menu" for tweaking.

1. Abyss ASV Table Menu
2. Install Abyss Script
3. Delete Abyss Script
4. Create Backup EFS
5. Clear init.d folder
6. Tweaks Service Menu
7. Advanced Abyss Menu
8. Abyss ASV Bus Table Menu

Sorry, but I can't give information about all of them. However, I can teach you how to tweak the most important settings which I highlighted in bold. These tweaks can optimize the battery life and performance of your SGS2.

Abyss ASV Table Menu

This enables you to adjust the voltage or amount of battery power your SGS2 consumes on a given clockspeed/frequency. Low voltage equals good battery life. Under this setting, you can choose from eight (8) options ranging from ASV Table 0 to ASV 7. I'm going to spare you from the headache and tell you this:

"The higher the number, the better its power efficiency."

I haven't really this theory but judging by the voltages from this XDA thread, ASV Table 7 is the most power efficient whereas ASV Table 0 is the least power efficient. The default ASV Table for Abyss Kernel is 3. The voltages of ASV Table 3 are lower than the original setting of the SGS2 which explains why Abyss has an impressive battery life.

There's an additional option under Abyss ASV Table Menu that says "Don't use ASV TABLE (for script)". I don't know anything about scripts so I didn't select this.

Tweaks Service Menu

• Enable sched_mc power savings - Better battery life, less performance
• Disable sched_mc power saving - Better performance, less battery life
• IDLE Mode Menu (affects the idle mode of your SGS2)
• IDLE Enable - Normal idle. Least battery efficient but phone wakes easily. Clockspeed is 0 but CPU still draws power, resulting in battery drain even when idle.
• AFTR Enable - Deep idle. More battery efficient but phone takes time to wake. Clockspeed is 0 and CPU power is killed. The phone will rely on L2 cache power to wake. The battery barely drains during Idle Mode in this setting.
• IDLE + LPA Enable - Similar to IDLE Enable but L2 cache power is removed. Thus, it provides better battery efficiency than IDLE Enable.
• AFTR + LPA Enable - Similar to AFTR Enable but L2 cache power is removed. This is the most battery efficient IDLE Mode. 
• Restore default - restores the default IDLE Mode for Abyss Kernel.
• Enable EXT4 Boost - Increases disk performance
• Disable EXT4 Boost - Normal disk performance
• Enable BLN - Enables back light notifications. The capacitive buttons of your SGS2 will light up for notifications when your phone is idle. Promotes battery efficiency.
• Disable BLN - Disables back light notifications. Your entire screen will light up for notifications. 

Advanced Abyss Menu

• Second Core Menu
• Hotplug on - TBH (To be honest), I don't know how it works but this is the best option under this menu if you want your SGS2 to have a balanced battery life and performance. Abyss Kernel has its own hotplug called "abyssplug"
• 2 core always off - Switches to single-core power. Offers great battery life but compensates performance of your supposed-to-be dual-core SGS2. I believe this will heavily impact 3D games. BTW add me on Dead Trigger "shetalksandroid" lol.
• 2 core always on - Forces 2 cores to run. Always. Even on idle mode. Offers great performance but obviously drains battery fast.
• Vibration Level Menu - Select from Level 0 to 6 where "Level 6" is the strongest vibration intensity. Choose Level 1 to help save battery.

ASV Bus Table Menu

Bus speed determines the speed of data transfer. Between ASV Bus Table 0 to 6, 0 is the slowest and 6 is the fastest. I did some benchmarks using CF-Bench while on default ASV Bus Table (which is unknown) and ASV Bus Table 6. Under Bus Table 6, many values increased including the Overall Score. The phone does heat up for no reason when set to ASV Bus Table 6 so I would suggest experimenting with lower values. Or, you can always select "Default ASV Bus Table."

Final word...

Well, I hope I helped you learn some things with this post. This has really been a great experience for me. Okay, at first it gave me a headache (and many things still do!) but at least I learned new stuff. I plan to test more kernels on my SGS2 and invest on benchmark tools. For consistency, I will only use stock XXLPX firmware to test these kernels.