I've seen a few different posts in some of the kernel threads debating whether SetCPU is helping or hurting battery life. SO, I'm just kind of curious to see what results are on a larger scale? Based on your own experiences, do you have SetCPU installed and if so, does it help or hurt battery life generally? Also, if you do have it installed, do you use profiles? What are the most beneficial settings to use?
1. Not in right section
2. SetCPU not intended for battery life
3. It only adjusts CPU clockspeed
4. This thread is mostly meaningless
5. It's been discussed ad nauseam.
charnsingh_online said:
1. Not in right section
2. SetCPU not intended for battery life
3. It only adjusts CPU clockspeed
4. This thread is mostly meaningless
Click to expand...
Click to collapse
SetCPU is not intended for battery life? Go to the Market and look at the description. If I posted this in the wrong section I apoligize. But, I think you are mistaken with your comment about SetCPU not being intended to increase battery life or increase performance...
THATTON said:
SetCPU is not intended for battery life? Go to the Market and look at the description. If I posted this in the wrong section I apoligize. But, I think you are mistaken with your comment about SetCPU not being intended to increase battery life or increase performance...
Click to expand...
Click to collapse
SetCPU only sets clock speeds and governors already in the kernel. If you just install SetCPU and adjust no settings your battery life will not change. Thus, "does SetCPU help battery life?" is utterly and completely meaningless.
Discussion of different governors and clock speeds has occurred (and is still occurring) ad nauseum and is really more suited for the General forum.
Thread moved as it does not pertain to N1 development.
I see very little gains from setcpu but I use it because I purchased it from the market and why not use it if you bought it right?
This method does not apply to drug addiction LOL
-Charlie
bri3d said:
SetCPU only sets clock speeds and governors already in the kernel. If you just install SetCPU and adjust no settings your battery life will not change. Thus, "does SetCPU help battery life?" is utterly and completely meaningless.
Discussion of different governors and clock speeds has occurred (and is still occurring) ad nauseum and is really more suited for the General forum.
Click to expand...
Click to collapse
lol Why would you download an application, not use it, and expect results?
If you throttle your CPU down you WILL get better battery life. My phone is set to never go over 600mhz and I get bettter life with it than if I turn off setcpu altogether.
charnsingh_online said:
1. Not in right section
2. SetCPU not intended for battery life
3. It only adjusts CPU clockspeed
4. This thread is mostly meaningless
Click to expand...
Click to collapse
You have a lot of knowledge, this is obvious but you're unnecessarily harsh (mean).
It's boring but's it's a legitimate question because people still make inaccurate conclusions about CPU and battery life. Those of us with some knowledge can really help those that are trying to understand.
#2 above is correct. But the question remains, does a forced lower clock speed ceiling have an effect on battery life? It could do, of course it could, but without a baseline and a control environment it's impossible to prove either way. I suspect the OP is simply looking for subjective opinions.
And on this basis I offer:
The CPU only has a material effect on battery drain when it's being utilised.
When the Nexus CPU is not required to work it idles using the lowest power possible
The radio (network) interface is the second most demanding element of on your battery over time (next to the display). Although the CPU peak demand is higher than the radio.
SetCPU does not impact radio battery use.
SetCPU can not have a positive effect on battery usage if it's using more power to run it's clock cycles.
SetCPU can force the processor to use less power (wind down speed).
Slowing the processor means some tasks will take longer to perform.
If those tasks require a high-drain elements (display, radio, WiFi or BT for example) then it's counter-productive (battery wise) to slow them down.
However, because CPU power consumption does not have a liner relationship to clock speed, then some tasks that don't use high-drain elements will consume less power to complete.
So, whilst it's unlikely that your battery life will benefit from the use of SetCPU alone there is a chance that it will.
SetCPU is a fantastic app designed for overclocking, the profiles are niche facilities that may offer battery benefit to a narrow range of users.
Hey djmcnz thanks for the indept look at this app but more importantly thanks for showing respect to those of us who are just learning. We all have to learn information at some point and there are people that forget that at one point some one had to tell them.
Thank you for the clarification on that! Djmcnz-that was exactly what I was looking for in terms of an answer. I really appreciate you taking the time out to explain everything for me and anyone else that may have been curious.
charnsingh_online said:
1. Not in right section
2. SetCPU not intended for battery life
3. It only adjusts CPU clockspeed
4. This thread is mostly meaningless
Click to expand...
Click to collapse
Don't know why you're so pissed off by a thread...
1. Not a very big issue. We have mods here to take care of this.
2. I don't know if SetCPU affects battery life or not but similar thing on a PSP device does increase the battery life. I have tried it on my PSP and setting the clock speed to the lowest acceptable level (depending upon what you're doing) does help maximizing the battery life.
3. You're absolutely right here.
4. Don't know what to say man.. but being a little humble doesn't hurt....
I never meant to be rude. I always get pissed off when people post in wrong sections Seriously. If people post in right section it just frees up moderator time. And about CPU nexus CPU has same voltage for many frequencies like 998,960 have same voltage. Going so down doesn't mostly benefit. So setcpu is only good for overclocking IMO. Display uses most of the power along with radio n CPU is one of those in middle of usage maybe 3rd or 4th. So underclocking will give a big battery boost is just a placebo. Atmost 10 minutes more is what underclocking can provide. N its not worth sacrificing the performance. Go for something underpowered if u want to underclock IMO. So setcpu serves more purpose of power than battery
I use it for the cool widget and standby/idle profile. B-)
you know what?youre allright.i follow your threads and you explain things well for someone like me learning all this ****.i got no time for keyboard commandos.thanks for the explanation.
djmcnz said:
You have a lot of knowledge, this is obvious but you're unnecessarily harsh (mean).
It's boring but's it's a legitimate question because people still make inaccurate conclusions about CPU and battery life. Those of us with some knowledge can really help those that are trying to understand.
#2 above is correct. But the question remains, does a forced lower clock speed ceiling have an effect on battery life? It could do, of course it could, but without a baseline and a control environment it's impossible to prove either way. I suspect the OP is simply looking for subjective opinions.
And on this basis I offer:
The CPU only has a material effect on battery drain when it's being utilised.
When the Nexus CPU is not required to work it idles using the lowest power possible
The radio (network) interface is the second most demanding element of on your battery over time (next to the display). Although the CPU peak demand is higher than the radio.
SetCPU does not impact radio battery use.
SetCPU can not have a positive effect on battery usage if it's using more power to run it's clock cycles.
SetCPU can force the processor to use less power (wind down speed).
Slowing the processor means some tasks will take longer to perform.
If those tasks require a high-drain elements (display, radio, WiFi or BT for example) then it's counter-productive (battery wise) to slow them down.
However, because CPU power consumption does not have a liner relationship to clock speed, then some tasks that don't use high-drain elements will consume less power to complete.
So, whilst it's unlikely that your battery life will benefit from the use of SetCPU alone there is a chance that it will.
SetCPU is a fantastic app designed for overclocking, the profiles are niche facilities that may offer battery benefit to a narrow range of users.
Click to expand...
Click to collapse
djmcnz said:
You have a lot of knowledge, this is obvious but you're unnecessarily harsh (mean).
It's boring but's it's a legitimate question because people still make inaccurate conclusions about CPU and battery life. Those of us with some knowledge can really help those that are trying to understand.
#2 above is correct. But the question remains, does a forced lower clock speed ceiling have an effect on battery life? It could do, of course it could, but without a baseline and a control environment it's impossible to prove either way. I suspect the OP is simply looking for subjective opinions.
And on this basis I offer:
The CPU only has a material effect on battery drain when it's being utilised.
When the Nexus CPU is not required to work it idles using the lowest power possible
The radio (network) interface is the second most demanding element of on your battery over time (next to the display). Although the CPU peak demand is higher than the radio.
SetCPU does not impact radio battery use.
SetCPU can not have a positive effect on battery usage if it's using more power to run it's clock cycles.
SetCPU can force the processor to use less power (wind down speed).
Slowing the processor means some tasks will take longer to perform.
If those tasks require a high-drain elements (display, radio, WiFi or BT for example) then it's counter-productive (battery wise) to slow them down.
However, because CPU power consumption does not have a liner relationship to clock speed, then some tasks that don't use high-drain elements will consume less power to complete.
So, whilst it's unlikely that your battery life will benefit from the use of SetCPU alone there is a chance that it will.
SetCPU is a fantastic app designed for overclocking, the profiles are niche facilities that may offer battery benefit to a narrow range of users.
Click to expand...
Click to collapse
HUH English Please
Kidding
mikey1022 said:
huh english please :d
kidding
Click to expand...
Click to collapse
34567890
Personaly done many tests and the result was:
Test config: WiFi tethering all the way, screen 100% Playing video all the time 2G only
4:10 @ 245Mhz hard
3:30 @ 998Mhz hard
No use actually - using N1 on 245Mhz is impossible - too sluggish.
SetCpu is ussefull:
1) If u have OC kernel to set OC mode for games like Asphalt
2)For letting android vary frequence ondemand instead of 998 all the time
3)For downclocking while in sleep mode (why use full power when u dont use it?)
4)For using Failsafe profile, to prevent battery and hardware damage.
That's all.
No use trying saving battery setting profiles like 100% - 998, 50% - 576, 20% - 499. This is useless.
On UV kernels the same thing +\-30 minutes battery life. And UV kernels themselfs dont give segnificant battery life increase, only lags and unstability ti system.
Dont believe me try yourself - Create yourself some actions fo testing and repeat them 2 time (Min cpu and Max cpu) on any kernel. Results will be very close.
SeriousX said:
3)For downclocking while in sleep mode (why use full power when u dont use it?)
Click to expand...
Click to collapse
The CPU steps down to it's minimum speed by itself. It never uses more juice than it needs to.
As far as i know, it is always at maximum, but maybe im wrong and you are right - then theres even less sence in this app.
Spreadsheet of the Battery Drain Data
BATTERY DRAIN BENCHMARKS
VIDEO of how it's done! (Do NOT try it yourself!)
NEW: Lab study done by nathanson666 see here and featured on the XDA's portal and twitter here.
Summary of Results
#1 - With screen on, if the processor is Idle, 100MHz saves the most power.
#2 - Regardless of your choice of governor, even with extreme undervolting, you are not going to be able to increase your battery life by more than 2%. (Click here for explanation.)
For the instability introduced by UV, it seems a 2% increase in battery life isn't really worth it! REMEMBER rebooting uses so much power, a single one would more than undo any savings made by UV.
#3 - The most power saving governor is Ondemand. If you need a high performance governor, use smartassV2, which offers some battery savings.
#4 - This is one point that everyone ought to know, but I'm including because many people seem to believe in myths: if the screen is off, and the CPU is not active, neither deep idle nor UV will have any impact on battery life.
#5 - The matr1x kernel by mathkid95 mainly saves power through UV of the INT voltages. You may need to raise these if you have freezes/reboots with your phone (in addition to raising the ARM voltages). I found that a maximum of 1 mA can be saved through INT UV, regardless of whether the CPU becomes idle (or with screen off in deep idle), so this is a constant saving. However, it is a very small saving, and doesn't apply if the phone is asleep. Remember, reboots cost more juice than UV can ever save.
#6 - If you have an amoled display, black saves a great deal of power. After that, red. If you have a black and red theme, this is saving you power!
#7 - If you are determined to UV, I found that my phone would become unstable with UV settings that were fine when the battery was fully charged. So check what UV your phone can handle when your battery is nearly empty. Again I say: Because of the high likelyhood and massive battery drain that comes with a reboot, I highly recommend you DO NOT USE EXCESSIVE UV. Also remember, even with extreme UV, you will not increase battery life more than 2%
#8 - I found that with bluetooth or GPS preventing the TOP=OFF state, there was no additional power saving from Deep Idle, i.e. the TOP=ON state does not save power.
#9 - Kernels with the 65 fps hack will cause the screen to drain about 10% more power compared to the usual 56 fps.
#10 - Conservative does not save power! For further details and exceptions, refer to my new thread: here.
#11 - This is just general advice: if you are having very poor battery life, have you tried turning auto brightness off? And if you've got no reception, you might as well be in airplane mode, because searching for reception also eats battery.
#12 - If your phone can't handle OC (or UV for that matter) it's because components in general are built to cost, which means factoring in tolerances, and every chip is made as cheaply as possible within the specified tolerances. Outside of those tolerances, whether your chip can cope or not is unfortunately down to the whether you got lucky with the individual device that dropped off the manufacturing line.
ARM document on A8 fault tolerance: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0344k/Babhjhag.html
In fact I measured how UV in particular can cause errors, and saw in action the A8 using MORE power to correct the errors. From my spreadsheet:
At 100Mhz
mV 1500 4.92mA
mV 950 2.83mA (default mV)
mV 800 2.58mA (UV saves some power)
mV 750 2.96mA (Extreme UV uses MORE power)
Same test but with Deep Idle enabled:
mV 1500 1.91mA
mV 950 1.49mA
mV 800 1.29mA
mV 750 1.49mA (Same result again but with DI enabled)
Referenced from my spreadsheet starting row 41.
Recommended reading: http://everything2.com/title/wafer+yield
Stock voltages for reference:
ARM
1000MHz @1250mV
800 MHz @1200
400 MHz @1050
200 MHz @950
100 MHz @950
INT
1000MHz @1100
800 MHz @1100
400 MHz @1100
200 MHz @1100
100 MHz @1000
Summary of Power States by tchaari (thanks!)
After research, and some explanation from Steve Garon, it is clear that Deep Idle & CPU Idle are two completely different things:
1) Three main CPU states are implemented in the standard android kernel: NORMAL, IDLE and SLEEP
2) Ezekeel added an intermediate 4th state: Deep IDLE. This saves more power but only when the processor has a background task to run while screen is off. Bedalus proved here that it really saves a considerable amount of power in particular cases (e.g. music playing when screen is off). A minority of users are reporting some slight instabilities with it, but they may in fact be caused by things other than deep idle.
3) The CPU IDLE backport is a replacement of the standard android kernel drivers used to put the CPU in idle/sleep states by the new ARM methods integrated in the linux 3.2 kernel. This backport is theoretically supposed to improve battery life (with just the basic 3 CPU states). It is 100% stable but no power saving has been shown either in bedalus' amp meter measurements, or Harbb's overnight drain tests.
Where did the other benchmarks go?
All ICS ROM Benchmarks: this thread
Kernel Features and Benchmarks: this thread
CPU Governors and I/O Schedulers: this thread
Power Saving Governors: this thread
Thanks to all the developers, and a big shout out to: Harbb for his dedicated testing; tchaari for his motivation, great ideas and inspiration; jcolinzheng for the idea to test Deep Idle at fixed frequencies (genius); aLNG for links to interesting and useful articles; Steve Garon for demystifying esoteric kernel technicalities and his excellent kernel itself; everybody else who helped; and of course Ezekeel for making Deep Idle work, and for a stimulating debate!
Harbb joined in doing specific battery tests, using the phone's battery graph. This is based on the phone's own readings (State of Charge or SoC for short). It's not very accurate for an instant reading, but over time, it does become more and more accurate. Therefore, Harbb conducted some very long (10 hour) tests. To improve accuracy further, he waited for the level of charge to drop to around 80% before each test. This eliminates the another source of inaccuracy, that the first 10% of the battery tends to deplete rather quickly (due to normal wear and tear over its lifetime). In fact, I use Ezekeel's Battery Life eXtender (BLX) to stop the phone charging early (at a user defined level: I prefer 90%) to help slow the deterioration of the battery's maximum capacity by preventing heat damage caused as the battery tries to absorb the final dose of charge above 90%.
Harbb's Data
Harbb's spreadsheet
Here's a summary of Harbb's 10 hour test findings, in order of best battery drain:
- 15% - SmartassV2 with DI
- 16% - Conservative with DI
- 21% - Lazy with DI and SOMF
- 23% - Lazy with DI
- 36% - Conservative
- 39% - Lazy
- 39% - Lazy with CPU IDLE
- 44% - Lazy with Eugene's DIDLE
- 48% - Lazy with Eugene's DIDLE and SOMF
[where DI means Ezekeel's Deep Idle, and SOMF indicates that Screen Off Max Freq was enabled]
Power Misconceptions
1st Misconception:
There is a misconception about about 200MHz using the same power as 100MHz because the voltage is the same. There is an approximate formula for CPU power consumption:
CPU Power Draw = C x F x V^2 (where C=capacitance, F=frequency, and V^2=Volts squared)
Capacitance is a constant, so we can ignore it. Let's fill in the values for the lowest and highest frequencies:
100 MHz V=0.95 so V^2=0.9025
1000 MHz V=1.25 so V^2=1.5625
So this shows we have roughly an extra 70% power drain due to the voltage increase. However, the maximum frequency is 10 times the minimum, i.e. a 900% increase. So the dominant factor in CPU power drain is in fact the frequency. Roughly speaking, the frequency has 13 times more influence over the power drain than the voltage.
Therefore, the governor that keeps the frequency as low as possible for as long as possible will save the most power. This appears to be consistent with Harbb's finding that conservative saves the most power.
2nd Misconception:
Some people say that if they UV they can play a game on their phone for an extra hour. The most you can get from UV is 2% extra battery life (and it is not worth the reboot risk).
See post #4 for calculations based on the actual measurements taken from the phone.
Here is a more academic proof using the same formula from the 1st misconception:
CPU Power Draw = C x F x V^2 (where C=capacitance, F=frequency, and V^2=Volts squared)
Capacitance is a constant, so we can ignore it. Let's fill in the values for just the highest frequency with the stock voltages and then an extreme undervolt:
1000 MHz V=1.25 so V^2=1.5625 (stock volts)
1000 MHz V=1.2 so V^2=1.44 (the most UV my phone can handle with a fully charged battery)
This is an 8% saving. Happily, this exactly matches what I measured in the real test (see cell F62 in the spreadsheet).
Remember, only the CPU is saving 8%, the screen being on uses about 4 times as much power as the CPU even at its highest frequency. This reduces the power saving to at most 2%.
I am of course assuming the screen is on. For most users, this is correct, as their processor will not be under a heavy load unless the device is in use, and this almost always means the screen is on. If anyone can think of any circumstances where the CPU is under a heavy load, but the screen is off, and show that this happens to all users a high enough proportion of the time to be relevant to this calculation, please let me know. [/far fetched caveat]
Testing Methodology
Two videos are available, and note, a circuit diagram of test now linked within the battery benchmark spreadsheet. I've decided to share it publicly as I've now set up and run this test three separate times, with no major problems. So I've reclassified it from utterly reckless, to merely dangerously stupid. Do not under any circumstances try this with your own phone! You have been warned!
You cannot trust battery monitor widget. (More on that in the 4th post)
Here's a way to test Deep Idle without rewiring your phone:
Note - SOMF means Screen Off Max Frequency
Setup must be identical (apart from SOMF). Install battery monitor widget, set history update rate to 10 minutes (not particularly to monitor the battery, but just to act as a timer). Set to run without widget. Turn off all radios, turn off sync, turn off location services, put in airplane mode. Turn off any of Ezekeel's mods excepting (Deep Idle of course). Set up your music app to play the same song on a loop. Make sure all volumes are down. Phone must be in mute. Turn of auto-brightness just in case. Morfic told me that to avoid the problem of the battery not reporting itself properly you can begin both tests with the same charging procedure: charge while off overnight. In the morning bump charge for exactly one hour. Disconnect, boot, start music immediately. Power button to screen off. Leave phone for 48 hours (should be enough time to auto power off).
After the first test, check the history from battery monitor widget to see how long the phone was on for.
Repeat again but with SOMF set to on.
***
Here's more on metering the amps:
REMEMBER I ADVISE THAT NO ONE SHOULD ATTEMPT THIS.
If you're thinking this is something you'd like to try, you'll need:
1) An analogue multimeter or pure ammeter because a digital one will be difficult to read with constantly changing amps.
2) Two battery caddies with space for 3 AA batteries each.
3) Six rechargeable batteries. Use rechargable ones because the volts are a bit less, 3*1.35=4.05 - close enough to the spec 3.7
4) Lots of cables with crocodile clip ends
5) Some fine copper wire
If you're thinking of soldering something onto your battery, DON'T - you may accidentally make a short circuit that will be difficult to undo, and cause the battery to explode. Plus the heat of the soldering iron certainly won't do it any good. And don't solder anything onto your phone contacts, just carefully twist a few strands of copper wire around them, so they can be easily removed. REMEMBER I ADVISE THAT NO ONE SHOULD ATTEMPT THIS.
[Q] Why do I need 6 AA batteries when 3 would provide enough volts?
[A] My multimeter inserts a 600 ohm resistor into the circuit (yours may be less, and if so you will need different calculations to convert to amps). This resistor allows the multimeter to evaluate the amps by measuring the voltage drop across it. But the resistance will cause your phone to starve of power. Running a parallel battery to the phone will prevent it crashing when the voltage supply isn't sufficient for things like screen on+cpu max frequency+sdcard IO... This parallel supply should run directly to the phone, not through the multimeter. It can be disconnected when the screen is off, and will not harm the phone. Remember to reattach it before powering on your screen, or it is likely your phone will crash. I would advise to start with fully recharged batteries, and not connect the USB charger.
[Q] Won't the amps read half of what is actually being drawn?
[A] Yes, but you'll get the correct reading if you unhook the parallel battery.
[Q] Might I also be able to do that when the screen is on?
[A] Yes, but I recommend that you do that with everything possible powered off, wifi, 3G... etc... screen brightness minimum. Set your screen timeout to never, so that you have control over it with the power button. Always reconnect your parallel battery before changing from screen on to screen off, and visa versa. (Due to large power spike)
[Q] I want to try this. Should I?
[A] No, no-one should try this.
Miscellaneous
[Q] You claim you cannot increase battery life using UV beyond 2%. Justify yourself!
[A] When the processor is in use (i.e. not asleep or idle) UV does save a tiny amount of power. I tested with the most extreme UV my phone could handle. With a high performance governor, e.g. smartassv2, extreme UV would reduce CPU drain by 13%, or about 7 mA. With a governor that keeps the CPU frequency low, CPU drain would be reduced by about 18%, or 4.6 mA (weighted - see the spreadsheet starting cell H88).
Remember, these savings are limited to the processor, and only when it is active. For most users, this will mean the screen is on. For comparison, the screen on minimum brightness displaying black uses 9mA. On max brightness, displaying white, it uses 690mA. Let us assume some median value, ~350 mA.
A saving of 4.6 mA out of at least 350 mA (screen) plus 20 mA (CPU)
= 1.2%
A saving of 7 mA out of at least 350 mA (screen) plus 50 mA (CPU)
= 1.8%
So, regardless of your choice of governor, even with extreme undervolting, you are not going to be able to increase your battery life by more than 2%.
Articles and Documents
Diane Hackborn's article on the formula that produces the dodgy Android OS usage statistic in the battery menu:
https://plus.google.com/105051985738280261832/posts/FV3LVtdVxPT
(note, this bug is fixed as of Android 4.0.4)
Data sheet for the fuel gauge chip:
http://www.maxim-ic.com/datasheet/index.mvp/id/6621
Link to great article on SOC (State of Charge) http://www.mpoweruk.com/soc.htm >>> explains all the reasons why I don't trust battery monitor widget and the phone's own battery stats.
Great article on the difficulties of accurate metering (thanks aLNG):
http://low-powerwireless.com/blog/d...t-schemes-for-battery-powered-devices-part-1/
In the article DUT stands for Device Under Test
The implication is that DMM [Digital Multi Meter] voltage drop readings (to measure amps) take hundreds of milliseconds, a will miss instantaneous battery savings above this time window. However, I am using an analogue meter, the the needle responds to all current. Due to the mass of the needle, there is inertia to overcome, which provides a form of averaging.
Quote from the article:
"a GSM cell phone can have current pulses of 2 amperes that last approximately 500μs while the power amplifier is on and transmitting, and then drop back down to the milliampere level for the remainder of the 4.5 ms GSM cycle."
500μs is 0.5ms, so is 1 tenth of the 5ms GSM cycle. 2 amps at 1/10th of 5ms = average of 200 mA
When I ran the test with my equipment, GSM broadcasting uses at least 170 mA - see row 36. I think this is a nice proof that the analogue multimeter beats the digital multimeter hands down for dynamic amps (i.e. changes happening below the millisecond level.) I'm also very satisfied that my result is close to the result stipulated by the article. It improves faith that my readings are accurate.
[Q] What could add inaccuracy to the readings?
[A] The dBm scale assumes a resistance of 600 ohms, but the resistor has 3% accuracy which means it could be as high as 618 ohms, or as low as 584 ohms.
[A] Also, the scale is very small, so I've read the needle to the nearest fifth of a dB
Other articles (thanks aLNG)
A study of the mA drain of various components of a smartphone
http://www.usenix.org/event/atc10/te...rs/Carroll.pdf
An ARM presentation on unifying power management procedures in the kernel
http://elinux.org/images/0/09/Elce11_pieralisi.pdf
UPDATE: Undervolting the CPU tested (using nstools ARM+INT)
UPDATE: impact of different screen colours tested (amoled)
UPDATE: Running apps tested.
Please note, the running apps draw power for lots of different reasons, access RAM, CPU, I/O, Graphics, all use power, what's being displayed also uses power, eg a brighter 3D scene vs a darker 3D scene. But it does give an overall idea of what Amps might be pulled when you are using the phone normally.
Thanks for your hard works I'm impressed with the systematic research.
Many things just the theoretical possibility? just something we created in our minds...
mobile_pc said:
Thanks for your hard works I'm impressed with the systematic research.
Many things just the theoretical possibility? just something we created in our minds...
Click to expand...
Click to collapse
Indeed, i agree. Now, with no benefit to under volting, perhaps we can all suffer less reboots.
For kernel benchmarks and more, see here: http://goo.gl/mpeHI
I have undervolted and overvolted in GB with direct impact on the battery life. The fact your undervolting tests show absolutely no difference in battery drain make me think the settings aren't even applied.
Also this part of your spreadsheet seems to be a bit lacking. What frequency voltages were changed? 100MHz? 200Mhz? All?
The smallest voltage I've seen stable for 100MHz ARM seems to be 825mv, for example.
Cheers
polobunny said:
I have undervolted and overvolted in GB with direct impact on the battery life. The fact your undervolting tests show absolutely no difference in battery drain make me think the settings aren't even applied.
Also this part of your spreadsheet seems to be a bit lacking. What frequency voltages were changed? 100MHz? 200Mhz? All?
The smallest voltage I've seen stable for 100MHz ARM seems to be 825mv, for example.
Cheers
Click to expand...
Click to collapse
The frequency information is there in the first column, eg 400/400 means the min and max settings were both 400. If you're not changing frequencies you can get it down very low.
Yes, perhaps nstools is defective. However, i did get an instant reboot with the lowest setting. Want me to do a repeat in GB?
For kernel benchmarks and more, see here: http://goo.gl/mpeHI
So undervolting does nothing? That seems strange ...
Also what about using juice defender? Worth it ?
italia0101 said:
So undervolting does nothing? That seems strange ...
Also what about using juice defender? Worth it ?
Click to expand...
Click to collapse
Yeah, does nothing to save battery. I don't know what juice defender is?
Sent from my SNES
polobunny said:
I have undervolted and overvolted in GB with direct impact on the battery life. The fact your undervolting tests show absolutely no difference in battery drain make me think the settings aren't even applied.
Also this part of your spreadsheet seems to be a bit lacking. What frequency voltages were changed? 100MHz? 200Mhz? All?
The smallest voltage I've seen stable for 100MHz ARM seems to be 825mv, for example.
Cheers
Click to expand...
Click to collapse
Okay, I went ahead and tested Gingerbread (carbon, ICS themed Oxygen 2.3.1, android 2.3.7) using franco's last kernel for GB. Starts at row 329.
Neither extreme undervolting nor overvolting had any impact on the battery drain.
Juice defender is a battery saving app that basically d/cs the data and wifi when screen is off and reconnects when screen is on... also when screen is off it uses schedules to turn wifi/data on to receive stuff and sync
italia0101 said:
Juice defender is a battery saving app that basically d/cs the data and wifi when screen is off and reconnects when screen is on... also when screen is off it uses schedules to turn wifi/data on to receive stuff and sync
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Sounds sensible enough to me!
Sent from my SNES
Some reserves
bedalus said:
2 - If you use NStools to undervolt, don't bother. No gain to be had from undervolting either ARM or INT voltages. I tested this to the extreme. Check the spreadsheet, near the bottom. (Tested in both ICS and GB).
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First, I want to thank you for all your efforts in the benchmarks especially for the battery drain. However, I kindly have some reserves on this. Maybe undervolting does not save so much power at idle but at higher loads, energy can be surely saved. Besides, maybe the energy saved is too minimal for your analog multimeter and it can't be noticed on it.
This is the theory :
The switching power dissipated by a chip using static CMOS gates is C·V2·f, where C is the capacitance being switched per clock cycle, V is voltage, and f is the switching frequency,[1] so this part of the power consumption decreases quadratically with voltage.
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source : http://en.wikipedia.org/wiki/Dynamic_voltage_scaling
And this a more practical reference about a study made by tom's hardware on AMD Athlon clock, voltage and power consumption. I think it can be generalized (at a smaller scale) for our ARM processor in the nexus S:
It’s only when we change the voltage that we're able to significantly save more power--about 13 watts lower consumption, or a total of 20 watts compared to running without power management. That's a savings of 25%.
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source (you may also read the entire article. It is very significant):
http://www.tomshardware.com/reviews/processor-power-management,2453-9.html
Other scientific papers and studies can be also found stating that undervolting saves power.
Kind regards.
I also appreciate all the hard work you have done for testing, on both kernels and everything, but im going to "gingerly" throw my hat in with tchaari here...
The only way to actually test battery drain would be to attach a multimeter and let it drain all the way on every test, using every kernel, and every setting - multiple times to omit false positives. Obviously this is beyond the acceptable timeframe it would actually take to accomplish. anyone would go insane sitting there waiting.
there are nuances here that will affect results regardless how carefull one is. the program itself might suck juice, your kernel/gov choice affects how the program runs too...also the status of your battery makes a difference. is it past it's half cycle life? etc..then the multimeter is another massive factor. there are many many different types not saying yours is bad, but over the years as an electrician ive played with some that are $20 as well as $2000 - and they are a far cry from each other even though they both do the exact same functions!
The undervoltage is a prime example. there are so many factors that will affect the results it's unusual to see your sheet having barely any differences - when we know that undervolting does actually save you battery under loads.
so it's nice to see a massive sheet like you did, as it does give a good start point reference - but it should be used not as chipped into stone law either.
Thanks for taking the time to give a great, no excellent base line to work off of though and preform more intense testing if people would like to go that far.
t3xboar said:
there are nuances here that will affect results regardless how carefull one is. the program itself might suck juice... then the multimeter is another massive factor. there are many many different types not saying yours is bad, but over the years as an electrician ive played with some that are $20 as well as $2000 - and they are a far cry from each other even though they both do the exact same functions!
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What program? I'm playing a loop of silence in the music app to keep the processor awake.
The multimeter I'm using isn't fancy, but even if it's reading 10% down, it's doing it for all readings, so it's a fair comparison.
t3xboar said:
The undervoltage is a prime example. there are so many factors that will affect the results it's unusual to see your sheet having barely any differences - when we know that undervolting does actually save you battery under loads.
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What makes you say we know this? I want to get to the bottom of this, so i need to see a concrete source.
Tchaari posted the capacitance times volts squared times frequency formula. I know this, and when I adjust the ARM voltage by more than half a volt, i expect to see this:
0.8x0.8=0.64
1.5x1.5=2.25
That should be 3.5 times as much power use.
Now, double the power in the dB scale is a difference of ~3dB. 3.5 times ~5dB. And I can notice a change of 1/5th of a dB on my multimeter's scale. There was no change. Here is how i tested.
Start music. Go into nstools, set ondemand with min and max at the same frequency. Go to volt, select the lowest possible voltage for that freq and exit. Screen off, measure amps. Screen on, nstools, volts, highest volts this time, exit, screen off, measure amps. Result: identical.
Seriously, if you have a background in electronics, have a go yourself (NO ONE SHOULD TRY THIS THEMSELVES) and get back to me.
In theory, it should save power, but it isn't. I'd love to be able to say why. At this point i don't think it's a problem with nstools, because i got a crash the second i put the volts to minimum when i was testing on Steve's kernel in ICS.
Sent from my SNES
As contradictory as some of these results may (or may not) be, bedalus is in the right with his methodology as far as i can see. Though at this point nothing should be set in stone. Not yet at least.
A few people saying with UV that they get more screen on hours, up from 3 to 6 hours. I'll check amps pulled (with both UV and OV) with screen on next.
Sent from my SNES
bedalus said:
A few people saying with UV that they get more screen on hours, up from 3 to 6 hours. I'll check amps pulled (with both UV and OV) with screen on next.
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That is a good idea bedalus but it seems that undervolting gain is very minimal instantly. In a long period, it can make some difference in battery life...
I have also many doubts about how sensitive your amps-meter is? Since we are dealing with small values in our case, maybe a more sensitive device can measure some difference that yours can't...
Anyway, your work is very interesting and as Harbb said : At this point, nothing should be set in stone yet.
Just wondering if the screen is the major battery draw like battery stats show or if the CPU uses the most and if under volting makes a difference.
Sent from my Nexus 7 using Tapatalk 2
maybe a little,
#1 battery drainer is screen brightness...
Personally I don't think so. Just my opinion tho I'm no expert.
Sent from my Nexus 4 using Tapatalk 2
The power dissipated by a chip is calculated by C*V²*f (V = voltage, f = frequency)
So undervolting will lower the power consumption a bit, but not much in comparison to the screen. Real life difference will be minimal.
Undervolting the 1.3Ghz step from 1.075v to 1v will theoretically lower the power consumption at that step by 15%. But the tablet spends most of its time in the lower cpu steps, where undervolting much is not that simple to accomplish. Don't expect huge differences.
no
I think it does a bit plus it reduces the heat a bit .
Sent from my Nexus 7 using xda premium
The big battery eater on the nexus7 is the screen, not the cpu. You will save way more juice by setting your screen to not be maximum brightness than you will by hacking up the kernel and undervolting.
Think I've read somewhere you may save 3% or so, the real saving is the reduction in temperature
Sent via TCP/IP
I can give a similar general consensus as the others. On smaller devices like my old evo 4G, Undervolting, especially at the lower end of the frequency chart, made a very noticeable improvement, but on a tablet device or device with a larger screen, the quantitative difference quickly dissipates. Undervolting may still help a decent bit in standby time (which I'd argue tablets spend in than phones) but screen on will make only a minimal change.
spankmaster said:
I can give a similar general consensus as the others. On smaller devices like my old evo 4G, Undervolting, especially at the lower end of the frequency chart, made a very noticeable improvement, but on a tablet device or device with a larger screen, the quantitative difference quickly dissipates. Undervolting may still help a decent bit in standby time (which I'd argue tablets spend in than phones) but screen on will make only a minimal change.
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Actually there is no saving while in standby; the cpu goes into the deep sleep state which already uses very little power. While I can't say I've seen battery life improvements from undervolting, it sure keeps the device cooler.
Sent from my SGH-I777 using xda premium
hy there,
im on latest sokp rom on my g2 (d802)
i want to get more juice from my battery, so I setup my core setings at 1036 mhz max and minimum 300 mhz.
wil this provide me a lot off battery in real life and will it also reduce heat ? even if i watch hd movie or play graphical games
In theory yes it should but not as much as you think cause it will be offset because it will have to keep a higher frequency for a higher period of time. Temperature should be reduced a lot but keep in mind games will lag if they need the extra power
drivenby said:
In theory yes it should but not as much as you think cause it will be offset because it will have to keep a higher frequency for a higher period of time. Temperature should be reduced a lot but keep in mind games will lag if they need the extra power
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hmm, well after i underclocked i played asphalt 8 for like 20 mins and game performance did not changed significantly. and i feel that the phone is now cooler then before when multitasking stuff.
is there also another way that can realy increase battery life besides underclocking.
abati said:
hmm, well after i underclocked i played asphalt 8 for like 20 mins and game performance did not changed significantly. and i feel that the phone is now cooler then before when multitasking stuff.
is there also another way that can realy increase battery life besides underclocking.
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Click to collapse
you also can try custom governors
Hey there, you may be suffering a placebo effect, it can give you a little extra juice, but in my opinion you get most of your battery with these 4:
1. Reduce timeout to 15sec.
2. Adjust screen brightness to be as low as possible (lux helps with this)
3. Eliminate vibrations of any kind (haptic feedback, notications that make your phone vibrate ex. whatsapp) and so on...
4. Data (Use Wifi if possible, 2g when you are not using your phone and airplane mode in some cases extend your battery for a lot too)
Don't expect to get more than 30 min of extra use changing your kernel configurations. ALTHOUGH if you are a heavy user (let us say, in this case, a heavy gamer) there are some kernel configurations you should check.
Also remember, if a task takes you 30min but only consumes 1 % per 30 min compared to doing the exact same task in 30seconds consuming the same 1% which one is worth it?
Phones hardware is way above the software we have available at this time, underclocking and undervolting is an option and you won't feel the difference but, as I've stated before, those are not the main issues of the battery drain.
I hope I've helped you out!
As the title sugests one of the main goals for everyone who scrolls and uses his OPO either to avoid awkward situations, for work or simply to check social networks etc, you want to have the best GOD DAMN Battery life you can possibly squeeze from your 3.1k mAh battery !
I am not responsible for any damage to your phone. Read before downloading or posting in the thread. Proceed with caution if you have no experience.
So to start off, i'm already assuming you have your OPO rooted, which is a must for this guide.
So you can go for any custom ROM of your choosing as long as it supports the Kernel of your choosing.
Before trying to say which Kernel is best, i'd like to state that I have a really simple philosophy which is,If it ain't broke don't fix it, so I go with the AK Kernel because it never failed me, has a really good comunity to back it up and is the only tested kernel for the OPO in the UKM Thread.
( Don't worry i'll paste the links to all of these things that I'm speaking of )
After you got your Kernel up and going you're gonna download the UKM ( Universal Kernel Manager ), which will enable you to use Synapse on your device.
So now you have the Kernel and UKM, which means it's time to flash them all.
Now flash your UKM file and after installing it flash the Kernel and you should be set!
Once the Phone has booted, just make sure to download Synapse from the playstore. I wouldn't recommend changing the voltajes on your cpu because you can really **** your **** up which no one wants!
I'm running with this profile for over 3 months and it has done me wonders ( pics below )
Synapse Screenshots
This means your CPU will be running 1.3 GHz less about 80% of the time, the suspended Cpu frequency will be 300-400 MHz lower and the GPU which goes to an all time high of 578 MHz every time you install a new custom rom will be lowered to 200 MHz. This will result in about 40% more battery AT LEAST.
I don't have any photos showing my battery time because i'm a bit stupid, but the next week i'll try to screenshot my battery life and show you, however, I do know that i'm averaging about 6 hours SoT with both Wi-Fi and Data turned on 24/7.
Also a really good and must have App that goes really well with this is Leandroid which makes your Data shut off after X minutes of the device being disabled. If you feel you're device is running low on battery because of uknown sources, I advise you to download Wakelock Detector to check if there is something keeping your cpu ramping up when it shouldn't be.
This is not optimal for a 3.1k mAh battery but, keep in mind that the memory leak issue is still in the works and this is the best I could do in the given situation.
Another point I would like to focus before ending this post is the screen brightness. We all know that Android L stock Brightness control sucks ( if you don't now you do ), so I recomend using Lux Lite, which controls your screen brightness by adjusting it whenever it receives more or less light in the sensor, and it has worked wonders for me, it you're interested in a profile I will link mine
Now I won't bore more, I hope this "guide" was helpful to you and if you liked it don't be shy to press the thanks button.
Links
Kernel
UKM
Synapse
LeanDroid
Wakelock Detector
Lux lite
THIS DOES NOT WORK WITH OXYGEN OS
TL;DR - limit all your frequencies to 1/2 of what your phone is capable of.
Theoretically it makes sense. But in real world if you do some thinking - the phone would do task X in 5 seconds @ max frequency then go to sleep. If you limit the clock to half of the original value - it doesn't use 2 times less power, it uses slightly less than max. However, you are forcing it to do that task in 10 seconds @ half frequency before going to sleep. This means that it will use more power to achieve the same goal.
I would advice you to find a suitable governor rather than deliberately making your device slower than necessary.
nitrobg said:
TL;DR - limit all your frequencies to 1/2 of what your phone is capable of.
Theoretically it makes sense. But in real world if you do some thinking - the phone would do task X in 5 seconds @ max frequency then go to sleep. If you limit the clock to half of the original value - it doesn't use 2 times less power, it uses slightly less than max. However, you are forcing it to do that task in 10 seconds @ half frequency before going to sleep. This means that it will use more power to achieve the same goal.
I would advice you to find a suitable governor rather than deliberately making your device slower than necessary.
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In all my runs with 2.5 GHZ and 1.2 GHZ I noticed a lot more difference running it with a lower clockspeed. ( 1- 1.30 hours more SoT )
I do know that the device requires more cycles to open an app while it's underclock however, i'm passing on what worked for me ( through some tests )
Hey can you tell me the procedure to flash on 05q??
I am trying to get good battery, now I am running franco kernel it does not give good battery. So if you can then please post the instructions.
Do you have root and recovery already installed?