[Sony Xperia T, TL, TX, V] nreuge:
I spend the last months to tweak my Xperia T and I wish to share my little experience here. Tweaks can allow to improve the device performances, battery life, smoothness, etc… Please feel free to share your own tweaks in this thread if you think it can be useful.

Your device must be rooted and CWM installed (for information, I use TiMiN8R’s rom ExperimenT 3.5).

First, if you have not yet them, you will need these apps :

Busybox

Root Explorer

A Terminal Emulator

Script Manager

Then, you must have init.d support enabled. Since the Sony stock kernel has not native init.d support, the best thing to do is to download this app : Universal Init.d. With it you will be able to activate init.d support.

Then, let’s tweak!!! But do not forget to do a CMW backup before applying any tweaks.

1. Simple init.d scripts

For instance, if you want to use the "msm-dcvs" CPU governor instead of the default "ondemand", just create a file containing this command line:

echo 'msm-dcvs' > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

Name the file with the name you wish, copy it in the /system/etc/init.d directory (with root explorer), check all the permissions and reboot.

To verify the current governor, open the termical and type :

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

It should show now: msm-dcvs

I noticed a slight better performance and battery life with this governor compared to "ondemand".

Then, let's change the I/O scheduler : noop is said better than the default cfq. So, create a init.d script containing this command line:

echo "noop" > /sys/block/mmcblk0/queue/scheduler

2. Simple build.prop tweaks

Use Root Explorer to open /system/build.prop

If you experience home redraws (after having closed a heavy app for instance) or systemUI lags, you can add these lines at the end of build.prop and reboot:

sys.keep_app_1=com.sonyericsson.home
sys.keep_app_2=com.android.systemui

The system will do its best to keep these apps in memory and you may experience less redraws or lags.

To ensure that your modifications are effective after reboot, just open the terminal and type :

getprop

3. Crossbreeder

This is a popular tweak (featuring 5 different key methodologies) that is said to bring better GUI performances, battery life, android usability, etc… Personally, I noticed an improvement in web browsing speed.

http://xdaforums.com/showthread.php?t=2113150

Read very carefully the entire OP before doing anything.

After flashing it, I've noticed a loss of the thumbnails in my social and news widgets. So, I’ve disabled the adblock options by typing this in the terminal :

su -c /system/etc/CrossBreeder/DISABLE_ADBLOCK

(I use Adaway to block ads, and it hasn’t such an effect).

4. Thunderbolt

This is another very popular tweak that is said to bring better performance and battery life. Personally, I noticed a significant improvement in performances.

http://xdaforums.com/showthread.php?t=1556013

Read very carefully the entire OP before doing anything. You will need Script Manager for the installation. Don’t use the remount option (no remount script available for Xperia T). I’ve not tested all the addons. The script sqlite is quite long at first launch, be patient (you can check end script notification in SManager), it is recommended to launch it once a week to defrag the databases.

With both Crossbreeder and Thunderbolt installed, I got no bugs or issues. These tweaks are not redundant, they focus on different things.

5. V6 Supercharger

I’ve tested V6 Supercharger (activating only the supercharge option). The installation is very long and boring. As a result, I’ve got several issues (like walkman and others resident apps in background stopping to work while web browsing). There are plenty of parameters to adjust during the installations and maybe I have not chosen the good ones for my device. Anyway, I don’t want to spend all my life to find them…

6. PurePerformances X

This is really THE mod that takes the best of all popular tweaks/mods (Crossbreeder, Thunderbolt, V6 Supercharger, and others) with several tasks automated (zipalign, sqlite, etc...). Moreover, it activates GPU rendering to save CPU with a said non-aggressive dithering (by default, GPU rendering is only activated if an app requests for it).

http://xdaforums.com/showthread.php?t=2360670

If you want to use it, first uninstall the previous mods (Crossbreeder, Thunderbolt, V6 Supercharger, etc…). The installation is quite simple, flash the zip and the installation script will determine by its own the best parameters for our device. Then, you can see a script named "add_to_buildprop.sh" in the zip that must be launched manually. I’ve lightened this script because it adds tons of tweaks to build.prop that are controversial or even prejudicial to the system stability of our device. So, I’m attaching 2 scripts : add_to_buildprop_1.sh and add_to_buildprop_2.sh. If you don’t want GPU rendering, use add_to_buildprop_1.sh, if you want GPU rendering use buildprop_2.sh. First, do a backup of the file /system/build.prop. Enable all write permissions on build.prop. Then, extract the script from the zip and copy it to the root of your internal memory (with Root Explorer). Open the terminal emulator and type :

su
sh add_to_buildprop_1.sh

Then, restore build.prop permissions and reboot. Personally, I’ve not noticed any goodness in using the GPU rendering.

(Update 27/10) : after deeper investigations, I've realized that the executable sqlite3 (databases defrag) provided by this mod is not working at all. I'm attaching a good sqlite3 for JB that is working fine. Extract sqlite3 from the zip, copy it in /system/xbin with Root Explorer and set all permission.

Overall, I think this mod is great. The boost in performances and smoothness is really noticeable in many areas of the system with battery life preserved.

7. Tuning the minfree settings (low memory killer)

All you need to know about minfree settings can be found here.

The default stock Sony minfree are: 8192, 10240, 12288, 14336, 20480 (i.e. 32Mb, 40Mb, 48Mb, 56Mb, 80Mb).

The PurePerformances X minfree are: 1280,2560,5120,7680,12800,20480 (5, 10, 20, 30, 50, 80).

They are rather "aggressive" and can cause frequent Home redraws or background apps unwanted closes. If you experience this, the best thing to do is to apply low minfree settings. Just create an init.d script with this command:

echo "1536,2048,4096,5120,5632,6144" > /sys/module/lowmemorykiller/parameters/minfree ;

Set all permissions and reboot (NB: if you use PurePerformances X, just modify the last line of the init.d script "ram_optimize", with the aforementioned values and reboot).

With these settings, no longer Home redraws or background apps closes but in exceptional circumstances. However, you may find that value will cause lag sometimes. Therefore, try these intermediate values (between the last ones and those of PurePerformances X) :

echo "1536,2048,4096,6144,9216,13312" > /sys/module/lowmemorykiller/parameters/minfree ;

It should be better. For me, rare redraws, no lag. At last, we can set the last value more "aggressive" as it concerns only "empty apps" and not the Home or the background apps. let's take the default stock Sony one :

echo "1536,2048,4096,6144,9216,20480" > /sys/module/lowmemorykiller/parameters/minfree ;

(i.e. 6Mb, 8Mb, 16Mb, 24Mb, 36Mb, 80Mb)

These are the ideal minfree values for me. Do not hesitate to play with these values to find the best for you.

To verify the applied minfree values, open a terminal and type :

cat /sys/module/lowmemorykiller/parameters/minfree

8. Definitely get rid of home redraws

Despite all these tweaks, home redraws can persist... Nevermind, a great app will help us!!

First, install the latest version (2.3.1) of Xposed Framework.

Then install App Settings v0.4 (don't install v1.5, it won't work).

Launch Xposed Installer and in the tab called "modules" tick the App settings and reboot.

Then, open App Settings and search the Home Laucher. Select it, swipe the button to turn it on and enable the "resident" option. Save changes and close the app. It will restart the launcher and after that home will be definitely locked in memory = no more redraws!! :)

After having done several tests on my device, I find that this method is safe and reliable (I've also added Walkman as resident, it prevent it to be killed during web browsing).

9. Let's swap!

To swap consist in using internal or external sdcard of the devive as virtual RAM. Although not used by default by android, it can be useful for heavy memory users. This is not a miraculous solution since virtual memory is usually much less fast than true RAM. However, it can help in certain circumstances.

All you need to know about swap can be found here.

It's much more efficient and beneficial to swap on the internal device sdcard rather than on an external sdcard. That's what the mod Turbo boost proposes to do. Read carefully the OP. Using this mod, I've tested many many different swap configurations and finally come to these two conclusions :

- The total swap size used must not exceed 200Mb, some lags appear for larger sizes.

- When the swap becomes full, some lags appear.

I've found this solution to overcome these issues:

- creating a 200Mb swap in cache partition,

- creating a 100Mb swap in data partition,

- set swapiness parameter to 60.

By this way the total swap size used hardly becomes greater than 2/3 of the total swap size and swap is never full. Swap size used finally stabilizes in the range of 150-200Mb (thanks to the swappiness parameter of 60).

Install intructions:

- download the attached 98swap.zip and extract 98swap_data_v300 and 98swap_cache_v300,

- move them in your init.d directory and set the correct permissions (or schedule them at boot with SManager),

- reboot,

- open a terminal and type free to verify that the swap has been created

- hit thanks in the Turbo boost thread.

- enjoy!

10. Other tweaks

Some other popular tweaks that I haven’t tested: Fly-On Mod, Pimp My ROM, Android Tweaker. Beware redundancies or incompatibilities that can occur if you install several mods.

Feel free to share your own tweaks or opinions of some tweaks in this thread if you think it can be useful.

Update 28/12/13 : §9. Let's swap!

Update 15/11/13 : §8. Definitely get rid of home redraws

Update 27/10/13 : Attachment of a working sqlite3 for PurePerformances X

Update 25/10/13 : Updated §7. Tuning the minfree settings, Better minfree settings

Update 22/10/13 : Better minfree settings

Update 21/10/13 : §7. Tuning the minfree settings (low memory killer)

Update 15/10/13 : §6. PurePerformances X

Thanks to [MENTION=5122093]WhiteNeo[/MENTION] for his active participation.