[Galaxy S Plus I9001 Android Development] hiej:
Vitality Kernel Voltage tweaks

A good way to improve battery life is to apply some undervolt to CPU.

On stock kernels is not possible to change the voltage, to do this kind of operation is necessary to use modded kernels like Vitality or SkyHigh.

To set voltages you need to use apps like, IncrediControl, SetCPU, AnTuTu CPU Master, etc... search them on play store

Looking on the following graphic, you can see that Vitality kernel does by default (red line) a undervolt compared to stok kernel (black dotted line),

My Idea is to try to use more lower voltage values, and based on my esperience using Castagna's Kernel on ICS and JB roms I've seen tha my device works very fine with Extreme UV version.

So I've applied the Castagna's EX-UV voltages values to Vitality with absolutely no failures. (See green line).

(I've had no failures also lowering voltages by 25/50 mV, see orange line)

As you know no all devices are identical, some are more low voltage friendly, some with too low voltages does not boot or not works properly.

So maybe instead to use EX-UV voltages you may try Castagna's standard UV values (blue line) that on high clocks is similar to standard Vitality.

Or maybe using intermediate values between Vitality defaults and Castagna UV / EX-UV.

Hint: after setting voltages vaules prior to stick them @ boot, do a normal usage of your phone for some hours, play games, run benchmarks to do some kind of stressing, verify that the phone is able to wake-up from deepsleep etc... If in normal usage yor are facing to some problems try use less agressive undervolt values, find right UV values is not easy but I think that playing with values between red and green lines of previous graph can be a good starting point.

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Credits to: CastagnaIT and Smeroni68

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Enable RAM SWAP feature

All credits are for defiant07

Do a look to this thread to thank him and for more information about SWAPITON script.

The RAM SWAP permits to have more free memory, that is useful to enhance performances on heavy app (specially games).

The trick is to force the phone to use a part of SD card memory as RAM. (More info about that are available using search button and google).

To do SWAP is need a kernel that features this option, like Vitality, Skyhigh and Brood Kernel.

How to check is SWAP is enabled

open terminal emulator and type:

free

the interface will show something like this:

The line corresponding to "Mem" voice indicates the RAM of the system total, used and free

The line corresponding to "Swap" voice indicates the size of swap memory: total, used and free, in this case the three "0" mean that Swap is disabled.

When Swap is enabled you should see something like this:

The line corresponding to "Swap" voice indicates the size of swap memory: total, used and free, in this case there's about 178 MB of extra free RAM.

How to enable SWAP

open terminal emulator and type:

su -c swapit

Now a semi-automated script will run, follow the instructions that are displayed on the screen and go to the end of process.

At the first usage the script will suggest to you a correct amount of "extra ram" to enable (in my case was 178 mb)

It will ask you a % of swappiness, set it with a value = 60 to no degrade too much foreground apps and multitasking, set it higher i you want to maximize performances for hard games.

It will ask you also how to set memory management, you have 3 options

- Similar to V6 Supercharger

- Similar to Kickass Kernelyzer

- A mid way of above options

(personally I'm running on Kickass option)

It will ask you where to place SWAP file, my suggestion is to select external SD, is slower, but because SWAP causes intense read/write operations the lifespan of the SD card could be compromised, so IMHO is better to burn a few $ esternal SD instead of the internal SD memory.

How to change SWAP parameters

When enabled, you can disable it open terminal emulator and typing:

su -c swapitoff

To re-enable it open terminal emulator and type:

su -c swapiton

To change swappiness level open terminal emulator and type:

su -c swapXX

where "XX" should be 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100

MORE info and options are available on the original trhread of the script, do a look here: http://xdaforums.com/showthread.php?t=2359182