yashsingh1/xdaforums huggingface dataset:
[Galaxy S II Original Android Development] droidphile:
1) Having only first core running can save 55-58% power compared to both cores online.

2) Only first core can hit deep idle. So if you set 2 cores to be online all the time, second core can not benefit from power savings offered by deep idle modes.

You can test by keeping the phone idle for half hour i) On hot plugging ii) On dual-core mode using tegrak app or script. You will notice that in second case, more battery was drained. I think it's best to set hotplug threshold to turn 2nd core ON to 100% or more during screen-off state so that core2 is never online during screen-off and core1 can 'peacefully' hit deep idle.
[Galaxy S II Original Android Development] ephraim:
Thanks for a very informative answer. Many will benifit from it :)
[Galaxy S II Original Android Development] Entropy512:
When it comes to power management, there's often no clear-cut answer.

Having the second core blocks deep idle, which is bad for power consumption in light loads. However, blocking AFTR is why it fixes the video decoding issues with .12. (They are caused by being able to hit AFTR in situations where AFTR was not possible before.)

Having both cores enabled doubles static power consumption - this is bad at low loads, but not a big issue at higher loads. Static power consumption is the power consumption which is dependent only on voltage but not on clock frequency.

So at moderate (especially multithreaded) loads - it makes sense to plug in that core early. Most people believe that unless a load is heavily single-threaded, it's best to hotplug the second core aggressively starting at 800 MHz and upwards. (However, if a load is single-threaded, the second core just sits and eats power.)

Basically, there are two contributors to CPU core power consumption (these are in addition to system power consumption, which is a whole other animal...)

Dynamic power - This is power consumed by every clock tick. It is proportional to clock frequency and to the square of the voltage.

Static power - This is power that is consumed regardless of whether the clock is ticking. It is proportional only to the square of the voltage.

Now, most CPUs (including ours) have advanced power management features that allow for the clock and even in some cases voltage to be shut off when the CPU is not in use. We have three idle states:

IDLE - Clock is shut off (dynamic power consumption goes away), voltage remains on (static power remains). So if a system runs at 50% load at 200 MHz it will use the same amount of power as 100% load at 100.

AFTR - Clock is shut off (dynamic power consumption goes away), voltage to core is shut off (a lot of static power consumption goes away), and I believe cache voltage remains (so some static power remains) - Here, 50% load at 200 MHz will consume LESS than 100% load at 100 if the voltage is the same.

LPA - Same as AFTR, plus I believe cache is also powered down. Even more static power consumption savings.

As to 200 vs. 500 and stock voltage being the same for these - 500 MHz also ups the clock of some peripherals and buses if I remember correctly, so it will consume a bit more overall power even if 500 MHz might save on core power consumption.

Edit: Note that if AFTR and LPA are blocked for some other reason, the power penalty for powering on the second core is VERY small. I believe this is why garyd9's hotplugging test over in another section (need to dig it up) showed little power benefit to shutting off the second core - the problem was they were done with the screen on AND USB debugging active with the device connected to a PC, which I believe will prevent AFTR from being entered due to interrupts being frequent enough to block it. (A number of people said to me that their video decoding issues disappeared if they had an active USB connection.)
[Galaxy S II Original Android Development] alcurtis93:
Had a lovely sod today after hanging up on a phone call. Last est kernel from hardcore. Anyone else experienced this.
[Galaxy S II Original Android Development] coloxim:
wow...thanks for the informations....

so i've undestand about 100 mhz...

but i've a dubt about second core...

is not more expensive(battery drain)one core at 500 mhz than 2 core at 500(250+250)...

thanks...
[Galaxy S II Original Android Development] b2rdetor:
Can't confirm that. 100 much better then 200 with deep sleep. When 200-1200 my phone loses 1%per 1.5 h but with 100-1200 only per 3 h. All syncs are on with wifi. Tested much more times.

Also lastest meizu phone have same exonus chip like galaxy s2 and its works with 100 minimal freq. Why?

Also you show us some incorrect diagrams which says that power drain will the same with stockvoltages200mhz and uv200mhz. But why?!!! How it can be possible? Stock 200mhz voltage are 900-950 mV but most people can uv it to 800-850. Seems like they don't use uv with 200mhz?

Also I don't know how phone operate when deep sleep, but i think that it all operations which need cpu uses wakelocks and cpu freq can be much more than 100 or 200 (800 with stock and 500 with siyah).

Also I have a question to entropy512

I don't need that problems with new cp

u idle driver but I want fixed bthid. Can I apply that fix to 2.6.11?
[Galaxy S II Original Android Development] tolis626:
Bull****.Your lowest frequency has absolutely nothing to do with deep sleep.If you do experience better battery life with 100MHz and it's not placebo,then the best possibility you have is that your phone doesn't deep sleep and just idles at 100Mhz instead of 200MHz.

Rest is physics and about the specific processor's design.Don't try to speak about things you don't know.Entropy512 knows what he's saying,as is droidphile and a bunch of other people.Until you are ready to do your reading,just try and don't ask questions.I'm not attacking you in any way,but cluttering the thread with that stuff(everyone,including me writing this) is pointless.Facts have a place here.Observations we are highly unsure of don't. :)
[Galaxy S II Original Android Development] b2rdetor:
You did not answer main question - how it can be - the same power drain with uv 200 and stock 200?

But the diagrams which showed us like proof has the same power with stock200 and uv200mhz

And my phone deep sleep are very good. Betterbattery stats say that all fine with deep sleep and wakelocks.

I also isn't attack that info. But I can't understand. And I believe only facts, but not people - even if its nickname entropy512 or else. Because we are people and we can mistake but with discussion we can find a truth

So what freq of deep sleep? With ondemand? Is it fixed or may be variable like 100-500?
[Galaxy S II Original Android Development] coloxim:
i belive in facts too....i've tried many times uv...and there are no benefits..

uv or not...nothing change..

i want to try a play music 1 hour with 100-1200 and 1 hour with 200-1200...

and see the differents...
[Galaxy S II Original Android Development] b2rdetor:
Uv makes power consumption much less.

Ill tested with proffesional multimetr power consumption and its very noticeable effect.

Asphalt6 with stock drain 1100-1200ma but with uv cpu gpu its only 800-900.
[Galaxy S II Original Android Development] tolis626:
So you want answers?Alright.

First off,the frequency at which the phone enters deep sleep is fixed and in Siyah it's configurable too via scripts.This frequency is 1000MHz on stock Sammy kernels and 800MHz on most custom kernels.It doesn't matter if your minimum frequency is 100MHz,25MHz or 1.5Ghz,your phone will enter and exit deep sleep at the same,fixed frequency.Now,if the suspend process goes haywire...Well,that's another kind of conversation and is irrelevant.All that is relevant is that it will cause battery drain that is for the most part undetectable by our current software(Unless I'm terribly mistaken on this one).

As for undervolting...First off,you have to realize that these voltages are measured in μV(microvolts,1μV=(10^-6)V=0.0000001V),just for the record.Secondly,while power draw is directly proportional to the square of the voltage,in low frequencies,as already stated by many people with better knowledge of the subject than me,things are different.In high frequencies voltages can play a big role in power draw and generated heat.But when clocks go all the way down to 200MHz or 100Mhz,other things take over in the power draw queue,like the radio and the rest of the SoC.At this point,it won't even make a perceivable difference if you undervolt,overvolt or leave it as it is.If the gains in battery by undervolting are real,they will at best be in the scale of seconds,probably even single digit numbers.Not to mention that you can't have the exactly same setup every time in every measurement,so these few seconds might be something else.

I also think that both Entropy512 and droidphile pretty much completely covered everyone on the subject of 100Mhz.I myself am using 100Mhz sometimes and 200Mhz at other times,trying to see if there is any differece.There isn't from my observations until now.

So,that good enough for an answer? :)
[Galaxy S II Original Android Development] b2rdetor:
Thanks for answer but

I understand that lower freqs has much less difference between uv and stock voltages, as you sad - because phone has radio part and other components. But, all of this parts are the same and we must see a difference between 200uv and 200stock. But on that diargams its a same power! Must be a difference - a little but must!

About deep sleep. I know that s2 inter in deep sleep and out of deep sleep with fixed freq, but I asked which freqs during deep sleep! Why we need deep sleep profiles for some of governors which operate with 100-500 or else freqs modified with unit.d scripts if deep sleep freqs are fixed? I think that deep sleep freqs are variable! 100-500 best values imho.

Also some people says that with on-screen profile 100 mhz are bad idea - because phone much more times need much more freq. But why my phone most of time if I don't touch them operate with 100mhz during on-screen ? It means that freq are enough. May be you use conservative? I sad later that it has a very bad low freq stability - its always try to jump to 500-800. Its a very bad governor for batery. Try ondemand and most of time you min on-screen freq will be 100.

Also why new meizu has min 100 with the same exonus chip?

Also why entropy512 says that with 100mhz power drain much more then with 200? Any reasons for that? Yes - difference between 100 and 200 will be istn very noticeable but 100 will drain less power.

100 are bad idea when you phone are unstable with that freq.
[Galaxy S II Original Android Development] teiglin:
Just to correct "the record" here, the voltages that are shown by Voltage Control are millivolts (mV), or .001V. Most people's voltage at 1200MHz is in the 1.1-1.3V range. Some scripts do set voltages by μV but then you're talking about hundreds of thousands or millions of microvolts...

I don't know as much as entropy or some of the other devs around here, but I can answer a few of these. I certainly can't say anything about why meizu would make a particular decision about frequencies, though name of the SoC in the GS2 is called Exynos, not exonus. :)

During deep sleep, the clock generator is shut off, so the "clock speed" is essentially 0.

The frequency that the phone enters deep sleep can be changed, of course, by a custom kernel. You might get a better answer from an expert, but my understanding is that setting the accelerate to sleep frequency too low causes sleep of death; I'm not sure anyone really knows why.

As for 100MHz taking more power than 200MHz, the short answer is that at 200MHz, the cpu can complete a workload faster and enter an idle state, while the 100MHz is active and using a comparable voltage for more time. I think entropy covered this fairly well; reread his descriptions of idle states or do more reading about low-power CPU architectures if you're still confused. I do think some blanket statements are being made that are inaccurate--it is certainly not the case for all workloads or usage models that enabling 100MHz will use more power than a 200MHz minimum.
[Galaxy S II Original Android Development] droidphile:
Refer this diagram. From Fig 1 blue line, you can see power consumption for constant 200mhz for different voltages. Power consumption almost doesn't increase at 850 to 900 to 1000mv for 200 mhz. That is why 200 mhz at stock voltage and UVed voltage has the same power consumption.

Frequencies used during screen-off state and deep sleep entering frequency are different stories.

Point is 200 mhz is more energy efficient than 100 mhz. It's not "100 is enough during screen-on".

Samsung did not use 100mhz because they know 200 is sweeter on exynos 4210.

Specific performance can be represented as power consumption per frequency.

This can be a representation of how much power the same task at the respective frequency required. The equation could be interpreted as a way of energy in Joules / 1 billion clock cycles.

Let representations be:

Constant for Static Power Consumption = SPC

and Constant for Dynamic Power Consumption = DPC

Frequency = F

Voltage = V

Then,

Joules/Cycles = (SPC/F + DPC) * (V^2)

This means at constant voltage, the energy per unit of work increases inversely with frequency. Since voltages for 200 and 100 are very close to each other, we can assume the voltage is almost constant for the equation corresponding to both freqs. This tells you why 100 mhz has it 1 W / Ghz and 200 mhz has it only 0.7 W / Ghz. This will not be the case for higher frequencies. We're only talking about 100 & 200.
[Galaxy S II Original Android Development] coloxim:
How did you test it?

UV CPU and gpu use less power?

Anyway, nexus developers said (after many tests) that UV is useless

Inviato dal mio GT-I9100 usando Tapatalk
[Galaxy S II Original Android Development] CamoGeko:
Lol, if UV is so useless then why has it been proven to improve battery consumption? As well as being supported and used by so many people.

Logged using an SGS2 type droid while floating in CheckROM quadrant...
[Galaxy S II Original Android Development] Holgott:
??mby a mistake in writing?
[Galaxy S II Original Android Development] www1:
Anytone can help me?

I use this kernel (very very good) but I have a problem.

My phone never go in deepsleep mode so I have a heavy battery drop.

I see it with cpu spy.

I try to install battery stast and in Partial Wakelocks I have this process:

Anyone can help to active deep sleep?

I reflash kernel 3 time and with wipe cache and dalvik cache.
[Galaxy S II Original Android Development] b2rdetor:
2 droidphile

OK right graf with const voltages shows as why 100 less efficient but graf shows us linear depence (line) but its not true if 200 more efficient

And other question - where from that grafs ? Its official samsungs? What device was used to take a power consumption in mw? Because all of you decisions from practical measurements. Or am I wrong?

Also that grafs only for full load? So what will be with low load. I don't say that 100 needs for full work (most of tasks requare more freq than 100) on that freq. But without any load (phone shows 10-15% load with 100 when screen on and no activity) what power consumption for 100 and 200 will be?

Also what about gpu? 40, 100, 160,200,267,400?
[Galaxy S II Original Android Development] droidphile:
Have a good reading here, in this translated page. Dummy battery, Voltcraft VC404, Grundig DM60, Swallow charger-discharger, etc were used for power, current and capacitance measurement.
[Galaxy S II Original Android Development] b2rdetor:
thanks, for article.

i made the same test near half year ago (you can read it here in russian http://4pda.ru/forum/index.php?showtopic=231945&st=820#entry9327477, very old testing, but interesting). but i tested UV and stock voltages with REAL apps like poweramp, video player, games (3d\2d), navitel, etc

but i did not tested constant voltage with diff freqs and constant freqs with diff voltages.

also - its just a manual testing and its can be a mistake!

also - its a test with a full load but not a test with low load.

also with low freqs 100\200 - overral power consumption are small and multimetr has a big error in results

so you must make you decission with off samsung docs but not that manual test.

its a very good testing but it can have a errors like my testing too!!!

tonight i wanna test

airplane+GPS off+BT off+minimal brightness

100mhz825mv with antutu (100%CPU load)

100mhz825mv with black onscreen without load

200mhz850mv with antutu (100%CPU load)

200mhz850mv with black onscreen without load

and ill put my result here
[Galaxy S II Original Android Development] rodries:
Has anybody tryed to compile siyah sources?

I get a hang when flash the compiled kernel

I have to use odin to fix my phone
[Galaxy S II Original Android Development] eric-filth:
Here using uv have difference.

I made test using antutu.

I ran 8x with uv and ran 8x without.

With uv 100% dropped 93%

Without uv 100% dropped 90%

The test is around 25min make counts of the benefic.

Enviado do meu Galaxy S2 usando Tapatalk
[Galaxy S II Original Android Development] eric-filth:
Sorry, double post.

Enviado do meu Galaxy S2 usando Tapatalk
[Galaxy S II Original Android Development] Entropy512:
This is the SiyahKernel thread, not the Speedmod thread.

Who? Where?

UV's improvements will be negligible under low load, because you're saving 3-5% on core power but the rest of the system is dominating power usage. They'll be noticeable under full load at upper clock frequencies, where CPU core power dominates the power budget.

http://xdaforums.com/showthread.php?p=21896408#post21896408 has some information where I take the classic power consumption vs. clock frequency equation and derive "energy per unit of work" (energy per clock tick) equations from it.

If the voltage to the CPU is constant (which it almost always is for 100 vs. 200) then the energy per cycle will be less at 200 than 100. Note that these equations assume the ability to enter deep idle states where the core power is shut off (LPA and AFTR in our case), eliminating static power when the clock is ticking.

If only the clock gets shut off (IDLE state only), then static power is always being consumed, and 100 vs 200 will perform identically in terms of power consumption.

.12 should improve the edge 200 has over 100 in power consumption, since the cpuidle backport makes AFTR easier to hit.
[Galaxy S II Original Android Development] coloxim:
I haven't link..I read it in nexus s thread(my ex-phone)..

OK..so UV in the high freq is good?

Inviato dal mio GT-I9100 usando Tapatalk
[Galaxy S II Original Android Development] JmPTaz09:
Yes, that's what he's saying. UV'ing will have a more desired effect on battery in the higher frequencies due to the reasons mentioned a few times. It apparently doesn't do as much at the lower frequencies.
[Galaxy S II Original Android Development] Entropy512:
Yup. The proportion of power consumption reduction should be related to the square of the voltage, so:

Pundervolt = Pstock * (Vundervolt/Vstock)^2

For example, if stock is 1300 mV and you run 1200 at 1.2 GHz, you'll save around 8% power on core power consumption. (I think I was wrong with my old estimates of 3-5% - if you can undervolt that much it'll be 8%) - At 1.2 GHz full load,

the CPU core is likely 60-70% of the power budget. (A bit less if the screen is at max brightness)

However, at 200 MHz, the CPU is likely only 5-10% of the power budget - even less at low load when it's hitting idle states. Saving 5-10% on something that's only 5-10% of the power budget to begin with means you'll maybe reduce power consumption by 1% at best.
[Galaxy S II Original Android Development] coloxim:
Ok..ok...thanks for informations..

Inviato dal mio GT-I9100 usando Tapatalk
[Galaxy S II Original Android Development] b2rdetor:
mass testing finished but i can upload results only after 12h (i havent time now)

GPU\CPU\CPUforce2xcores idle

GPU\CPU per frequence efficiency

GPU\CPU UV vs stock

PS: 100 mhz - its a very bad idea!!!!!
[Galaxy S II Original Android Development] karan999:
Im facing heating problems.On checkRom V5 with the latest Siyah kernel.Can anyone help ?

Regards,

Karan.
[Galaxy S II Original Android Development] ilikesamsung:
i'm still unable to mount a NTFS thumbdrive with my SGS2 via an OTG cable.. by right, this kernel should support. any help?
[Galaxy S II Original Android Development] droidphile:
All kernels should produce same heat at same frequency with same voltage level. Heating could be due to an app. It could be GPU OC or CPU OC.

Try scaling between 200-1000, use the phone for some time and re-check for the issue.

I have no prob mounting ntfs thumb. Check /mnt/usb. You will find all the partitions there, mounted as RW.

Make sure to unmount safely after use. umount /mnt/usb

If it says "device busy, can not unmount", try a lazy unmount

umount -l /mnt/usb [lazy unmount could be a little unsafe]
[Galaxy S II Original Android Development] ilikesamsung:
when i mount the thumbdrive, at my notification bar, it shows 'USB storage blank or has unsupported files'

what app u use to enter ur files? and what you mean by check /mnt/usb?
[Galaxy S II Original Android Development] Holgott:
Hmmm... newest CM9 changelog showing "LP6 Kernel". Does it mean kernel sources are available now?
[Galaxy S II Original Android Development] spaxx24:
No.
[Galaxy S II Original Android Development] Holgott:
ok. TY bro
[Galaxy S II Original Android Development] blumsen:
Quick question:

When Sammys official ICS is finally out, do I need to flash some official kernel first if I want to try it out, or is Siyah going to be ok with it? Or does Kies also overwrite your kernel at the same time it updates?

/Blumsen
[Galaxy S II Original Android Development] CamoGeko:
The ICS ROM will come with its own kernel. Siyah will not work with ICS.

Logged using an SGS2 type droid while floating in CheckROM quadrant...
[Galaxy S II Original Android Development] stylez:
OT:

http://xdaforums.com/showthread.php?p=22797498

[APP]Voltage Control - control OC/UV for OC kernels.

Might be nice to show appreciation "thank" since many of us use it ;)

Sent from the valley of the shadows....
[Galaxy S II Original Android Development] b2rdetor:
http://translate.google.com/transla...php?showtopic=231945&view=findpost&p=11645642

here you can read about ny testing

seems like that for UV minCPU 500Mhz may be even better than 200
[Galaxy S II Original Android Development] mekhonte:
Gokhan

I know you're busy but Plz releasE 2.6.13 ! You've made us addicted to flashing your kernels ;-) this time we've waited so long!
[Galaxy S II Original Android Development] veyka:
I'm pretty sure he's away working and getting married, the new version works perfectly so patience is a virtue!
[Galaxy S II Original Android Development] Vaedryn:
He is on his honeymoon after his wedding, i think he have more better to do than release a kernel
[Galaxy S II Original Android Development] Entropy512:
Well, there is the AFTR/MFC interop issue for some people - but there's a workaround for that.
[Galaxy S II Original Android Development] mekhonte:
I'm sure it will.and I'm so happy for him.
[Galaxy S II Original Android Development] :
BLN doesn't work any help??
[Galaxy S II Original Android Development] wurzelsepp3:
Thanks allot for your testing (especially the idle values which were missing in the other study),

Suprisingly 500Mhz as min_freq really seems to be the best choice in terms of battery life :eek:
[Galaxy S II Original Android Development] b2rdetor:
May be yes but may be not! Because 1 test says that 500 more energyefficiency but other - not.

Also I test only ma but not Watts. Need to test that. Take a phone always to screen on with same screen with limited 200 and limited 500. May be tomorrow I will do that.
[Galaxy S II Original Android Development] droidphile:
Gokhan is back! Let's stop whining and be a little more patient :)