[Sony Xperia T, TL, TX, V] Knutselmaaster:
Kernel Settings

Scheduler

The scheduler settings can have quite some impact on the system.

I've tested all of the commonly available and as a general find I can say that for all of them, the cache size gives the best results around 1mb (1024kb).

Furthermore, choosing the cfq scheduler helps enormously to stop the annoying sound glitches that I've witnessed on all of the newest roms during audio playback.

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Governor

To keep things simple, the Ondemand and Interactive governors both have their advantages and inconveniences, but these are certainly the two that have the best compromise between performance and battery life.

There are a lot of governor parameters we can change, with the right app.

Because of the availability of a special setting regarding the sound bug, I have been forced to use ondemand, even if I would prefer using the interactive because it gives me a smoother system and better battery life.

The scheduler setting seems very related to the sound bug, system smoothness and lags, so I looked for other possible IO related settings that might be helpful.

The ondemand governor has a setting called

io_is_busy

(true or false)

I googled what that does, and found out that it is preventing the CPU to clock down if the system is waiting for IO operations when set to 1 (true)

This setting does miracles for me, I get a lot more responsive system and it helps a lot for the sound bug.

I tried it with deadline scheduler (fastest for me) and it almost solves the sound bug, but with CFQ it works best.

The default setting is 0 (false).

It does have a small negative impact on battery because it keeps clocks high now and then, but it certainly isn't a lot.

I was forced to use Ondemand governor now, so I read about it and tried some settings to make it behave more like the interactive governor which gave me a better battery life and smoother system.

The ones that are quite effective are:

Powersave_bias

it sets a percentage of "effort" the system does to use lower clocks.

It is quite effective on battery stamina and the phone isn't really loosing a lot of "bite" or responsiveness when the setting remains around or under 10% (set to 100 for 10%, as it is a 0 to 1000 scale)

The default setting is 0 (disabled) so basically just a low percentage will activate the function and be unnoticeable.

I've set mine to 36.

Up-threshold

is the percentage of charge on the core before it goes up one notch in clockspeed.

Default is 90.

This setting helps a lot to get the processor go up in speed gradually, and remain in 80% region clockspeeds when more isn't needed.

Above 93 it becomes noticeable, but in a pleasant way as the UI doesn't spike from very slow to full speed, but it ramps up gradually.

It is good for battery and pleasant to the eye.

I have set mine to 95.

Sampling_down_factor

is the number of clock cycles the core remains at the same clockspeed when there is no more demand, before clocking down.

Default is 4.

I have searched all over the net but haven't found any reason why this is set to 4 clocks.

I set this to 1 and got better battery and less heat without noticing any difference what soever besides that.

I'm really happy with these settings, and I haven't had any problems playing around with them, no fc no bugs.

Just remember to

change 1 parameter at the time

and test it , and

change with very small steps

!

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Voltages

After the screen brightness, changing the voltages has the biggest impact on battery life.

It can also influence system performance, because with the extra heat generated by using too high voltages the thermal throttling will lower clockspeeds sooner and more often.

Attention!

Raising

voltages (too much) may permanently damage your phone!

Attention!

Lowering

voltages can only make your phone crash and restart without harm, BUT

be sure to test voltage settings before making them automatically applied on boot

to prevent that the system gets too unstable to change back the setting.

You would need to reflash to get it at the default setting.

Attention! There are three different versions of processor on our phones, each has a different voltage table.

Be sure to use the right one, that corresponds to your phone !

You can check what version you've got by comparing your default voltages with the table below.

Default Voltages

as used in all roms including stock,

except

some specific [MENTION=5122093]WhiteNeo[/MENTION] kernels.

These voltages don't allow any overclocking and cause heat problems when playing games in the sun etc.

"Slow Processor"

384mhz -=- 950mV

432mhz -=- 975mV

486mhz -=- 975mV

540mhz -=- 1000mV

594mhz -=- 1000mV

648mhz -=- 1025mV

702mhz -=- 1025mV

756mhz -=- 1075mV

810mhz -=- 1075mV

864mhz -=- 1100mV

918mhz -=- 1100mV

972mhz -=- 1125mV

1026mhz -=- 1125mV

1080mhz -=- 1175mV

1134mhz -=- 1175mV

1188mhz -=- 1200mV

1242mhz -=- 1200mV

1296mhz -=- 1225mV

1350mhz -=- 1225mV

1404mhz -=- 1237,5mV

1458mhz -=- 1237,5mV

1512mhz -=- 1250mV

"Nominal Processor"

384mhz -=- 900mV

432mhz -=- 925mV

486mhz -=- 925mV

540mhz -=- 950mV

594mhz -=- 950mV

648mhz -=- 975mV

702mhz -=- 975mV

756mhz -=- 1025mV

810mhz -=- 1025mV

864mhz -=- 1050mV

918mhz -=- 1050mV

972mhz -=- 1075mV

1026mhz -=- 1075mV

1080mhz -=- 1125mV

1134mhz -=- 1125mV

1188mhz -=- 1150mV

1242mhz -=- 1150mV

1296mhz -=- 1175mV

1350mhz -=- 1175mV

1404mhz -=- 1187,5mV

1458mhz -=- 1187,5mV

1512mhz -=- 1200mV

"Fast Processor"

384mhz -=- 850mV

432mhz -=- 875mV

486mhz -=- 875mV

540mhz -=- 900mV

594mhz -=- 900mV

648mhz -=- 925mV

702mhz -=- 925mV

756mhz -=- 975mV

810mhz -=- 975mV

864mhz -=- 1000mV

918mhz -=- 1000mV

972mhz -=- 1025mV

1026mhz -=- 1025mV

1080mhz -=- 1075mV

1134mhz -=- 1075mV

1188mhz -=- 1100mV

1242mhz -=- 1100mV

1296mhz -=- 1125mV

1350mhz -=- 1125mV

1404mhz -=- 1137,5mV

1458mhz -=- 1137,5mV

1512mhz -=- 1150mV

[MENTION=5122093]WhiteNeo[/MENTION] Voltages

are lower than the stock values and give very good results.

As his kernels also support overclocking, i will add the voltages for 1620mhz too.

Some reports of phones rebooting at sleep with these voltages are reported and can normally be solved by raising the voltages on the lowest clockspeed(s) a bit.

Never go higher than the stock values!

These voltages let me run the second core overclocked without any problems, but if I overclock the first core or both, my phone gets too hot.

"Slow Processor"

384mhz -=- 950mV

486mhz -=- 975mV

594mhz -=- 1000mV

702mhz -=- 1025mV

810mhz -=- 1050mV

918mhz -=- 1075mV

1026mhz -=- 1100mV

1134mhz -=- 1125mV

1242mhz -=- 1150mV

1350mhz -=- 1175mV

1458mhz -=- 1200mV

1512mhz -=- 1225mV

1620mhz -=- 1250mV

"Nominal Processor"

384mhz -=- 900mV

486mhz -=- 925mV

594mhz -=- 950mV

702mhz -=- 975mV

810mhz -=- 1000mV

918mhz -=- 1025mV

1026mhz -=- 1050mV

1134mhz -=- 1075mV

1242mhz -=- 1100mV

1350mhz -=- 1125mV

1458mhz -=- 1150mV

1512mhz -=- 1175mV

1620mhz -=- 1200mV

"Fast Processor"

384mhz -=- 850mV

486mhz -=- 875mV

594mhz -=- 900mV

702mhz -=- 925mV

810mhz -=- 950mV

918mhz -=- 975mV

1026mhz -=- 1000mV

1134mhz -=- 1025mV

1242mhz -=- 1050mV

1350mhz -=- 1075mV

1458mhz -=- 1100mV

1512mhz -=- 1125mV

1620mhz -=- 1150mV

@Knutselmaaster Voltages

I've spent a lot of time testing downvolting.

The following settings have been tested on my phone only, quite thoroughly, and should run good on every LT25i.

My phone is the "Nominal" version, and i translated values for the other versions by using the same logic as in the stock and [MENTION=5122093]WhiteNeo[/MENTION] ones.

Please give me feedback so that i can validate my results.

These voltages let me run both cores overclocked without any problem :)

"Slow Processor"

384mhz -=- 912.5mV

486mhz -=- 937.5mV

594mhz -=- 962.5mV

702mhz -=- 975mV

810mhz -=- 1025mV

918mhz -=- 1025mV

1026mhz -=- 1050mV

1134mhz -=- 1062.5mV

1242mhz -=- 1087.5mV

1350mhz -=- 1112.5mV

1458mhz -=- 1137.5mV

1512mhz -=- 1162.5mV

1620mhz -=- 1187.5mV

"Nominal Processor"

384mhz -=- 862.5mV

486mhz -=- 887.5mV

594mhz -=- 912.5mV

702mhz -=- 925mV

810mhz -=- 975mV

918mhz -=- 975mV

1026mhz -=- 1000mV

1134mhz -=- 1012.5mV

1242mhz -=- 1037.5mV

1350mhz -=- 1062.5mV

1458mhz -=- 1087.5mV

1512mhz -=- 1112.5mV

1620mhz -=- 1137.5mV

"Fast Processor"

384mhz -=- 812.5mV

486mhz -=- 837.5mV

594mhz -=- 862.5mV

702mhz -=- 875mV

810mhz -=- 925mV

918mhz -=- 925mV

1026mhz -=- 950mV

1134mhz -=- 962.5mV

1242mhz -=- 987.5mV

1350mhz -=- 1012.5mV

1458mhz -=- 1037.5mV

1512mhz -=- 1062.5mV

1620mhz -=- 1087.5mV

If the voltages are too low, the phone will tell you.

If the phone crashes in sleep, the voltages on low speeds are too low.

If the phone freezes in demanding apps like games, the voltages on the high speeds are too low.

If the system seems to freeze just shortly once in a while, the voltage in the mid-speeds is too low.

With some patience you can easily find the minimal voltages for your phone ;)

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Clockspeeds

Attention when overclocking, it generates exta heat that might damage your phone! Normally thermal protection will save you by lowering the maximum speed but there's no guarantees here!

Depending on a few factors, the V can be overclocked.

This can be done with only a few kernels and you need some luck as each processor is different.

On my phone, I can only overclock when I set the lowest stable voltages possible and I think I would have to disable it in extreme situations like playing Ingress in the full summer sun with my external battery plugged in.

If you're one of the lucky ones that has the "fast" processor (see voltages) then it should even be better.

Note that I also altered my governor settings to make my phone go up in clockspeed less quickly (see Up-threshold)

What is more interesting is downclocking at screen off.

My findings are that it is possible to use only the lowest clockspeed, without any bugs.

Music playback works as good as with the screen on and open applications will continue as they should.

The only thing is that it takes a bit more time for the phone to properly wake up when you unlock the phone.

That is why I set mine to max 486mhz, it is not much more but it totally solves the slowdown.

I think it is because using one single speed for min and max disables some process that regulates the acceleration or something like that....

Downclocking at idle really extends battery life but of course only when you don't use your phone often.

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Memory

1gb of ram is not much.

That is why the minfree settings are quite important.

To prevent memory filling too much (witch really makes the phone lag as crazy) the preset used needs to be at least aggressive and for better behaviour of open apps i advice to "de-agress" the first two values for foreground apps to the level of the light preset. (sorry, phone broke and i don't remember the exact values)

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