Hello,
It's a well know 'fact' that our P500 draws the same amount of power when clocked at anything below 480MHz, so underclocking it below 480MHz brings no battery benefits.
I have been trying to find the reason for this, but I can't find the thread / post in the search that details the reasons for this and how it was tested. My guess is that it's buried in one of the many bloated development threads... If someone can point me in the right direction that would be great.
Cheers!
I know this thread has a quote of this post and that this is a well known information but, besides this community common knowledge (by which I'm very grateful), I also can't find any specific data on this matter.
I even found this thread that aks the same thing, but it has no answers.
So it would be great if someone could give us a bit more information about this.
Thanks in advance!
480MHz and below use the same voltage. It takes more battery to jump from say 245 to the max freq
InfiniteRisen said:
480MHz and below use the same voltage. It takes more battery to jump from say 245 to the max freq
Click to expand...
Click to collapse
Yes, we all 'know' this but where did this information come from?
This post shows that it is a general MSM7x27 'feature' that all frequencies below 600MHz use the same voltage. This is where we assume this to mean that it uses the exact same amount of power whether it is running at 122, 245, 320 or 480MHz, so we're taking a speed hit for no power benefit.
Does anyone knows of any benchmark tests to confirm this? I might try some tests this week, set the min/max MHz to the same value and run a program to keep the CPU at 100% and see how long it takes to drain the battery (perhaps a huge pi calculation or something).
Which do you value more, source of information or proof now?
InfiniteRisen said:
Which do you value more, source of information or proof now?
Click to expand...
Click to collapse
Surely that's the same thing, a good source should also contain proof of the claims it is making...
I'm not saying it's wrong, but if nobody has tested it we can't be sure, right?
adfad666 said:
Surely that's the same thing, a good source should also contain proof of the claims it is making...
I'm not saying it's wrong, but if nobody has tested it we can't be sure, right?
Click to expand...
Click to collapse
On my personal experience, i would actually say 245mhz consume less battery than 480mhz. But I still prefer the latter as it's a bit more speedy. On battery life, it's just a <1% difference between the two.
as far as what ihve read!!people say it takes infact more power consumption when we underclock very low frequencies like 122 ,since it takes more work for the phone to operate in a laggy state with very less cpu frquency ..and thats the reason i think(not sure) why we are asked to have a minimum of 480mhz frequency though i prefer 320
Test setup suggestion:
Test 1 = Idle
Set to 480/480 set to airplane mode overnight and look at battery drain.
Do the same for 245/245
Compare results
Test 2 = Intermittent load
Set to 480/729- test using on/off series of tests not 100% all the time. You want the governor to scale frequently during the test
Same test above but @ 122/729
Compare results
This will give you 2 conclusions
1 - 480 at idle does/doesn't drain battery as much as 245
2 - Increased scaling does/doesn't increase drain battery.
The longer the phone is awake the more it drains battery. Also take note of how long it takes to complete test 2.
**EDIT**
Intel has done extensive laboratory testing showing the results of Speedstep and the results carry over to ARM and governor scaling.
I'm inclined to follow the crowd on this one, no increase in voltage = no increase in power draw. That's scientific fact.
Increase in frequency will increase heat. Unnecessary scaling will also increase heat. Increased heat leads to shorter battery life, consequently overtime the battery can't hold as much of a charge. So again, nothing decisive here to make me change my mind.
If you still want to, then proceed with the tests above.
Related
So this is a development idea...
I thought about this the other day and realized that under volting could be causing my battery to die quickly...
Here's why.
V = I * R
Where v = volts, I = amps, R = ohms.
P = V * I
Where P = (power)watts
I know some of you are going to think that this doesn't belong in development, but here me out here.
So if the processor uses 1.5 Watts and we decrease the voltage, this means that the processor needs to increase current to maintain that power. This equates to reduced battery life.
I'm just suggesting that undervolting may be causing the low battery life. If you know better feel free to tell me I'm wrong, but please explain the mechanics of what is going on not just your theory.
This question is over my head so I'll refrain from speculating directly on your theory. But real-world results with my undervolted Stupidfast 1.54 kernel gives me much better battery life than stock. Yes, this may be due also to the unbloated-ness as well so I'm not 100% certain the undervolting is the main help here
Well....I dunno how this applies to CPUs but.... I used to be a car audio installer/buff and when we noticed voltage sagging to an amplifier, the amplifier would compensate by pulling more amperage at the lower voltage. It never seemed to make much different to the batteries, but it did make the amps run much hotter...so....
Again, not sure if it would tie in, but....
Hmm I've never thought about that. From my RC knowledge the most efficient set ups are the ones that use high voltage but low amps.
I may have to try a OV kernel and see if I notice a difference...
Sent from my Samsung Fascinate running BH3.0, DL09, 125mv undervolt Voodoo5 using SwiftKey and Tapatalk
As a disclaimer, I have not performed any formal reading on this topic, these are just my idle ramblings.
My contention has been that you only enjoy the benefits of a UV kernel if you are a certain type of user.
If you are performing CPU intensive tasks, you reap the most benefit from the UV kernel because it needs less power to run at 1 GHz (or whatever the maximum clock speed is set to for that kernel).
If you spend alot of time idling, for instance reading interspersed by web requests, you are spending most of your time at the minimum clock speed. With the stock kernel, that is set to 0.1 GHz. With a UV kernel, the minimum clock needs to be set to something higher to keep the CPU running. You may be able to estimate what this speed needs to be based on the fundamental power calculations in the OP.
The governor quickly changes your clock speed based on your current usage & requirements. To make optimal use of the CPU governor, it should have access to the broadest possible range of speeds (without going higher than is useful/safe). Unfortunately, undervolting a kernel sacrifices some of the lower end of that range. Therefore, many users see much improved battery life, while others (like me) experience noticeably diminished overall performance from UV kernels.
Swyped w/ XDA App. When in doubt, mumble.
P=V*I
The processor does not draw a constant power, but it does have a minimum. The point of undervolting is bringing the power consumption to that minimum within the phones physical environment and user expectations of functionality.
So...
You are right.
However, processor frequency is dependant on current. Thus if you are undervolting to save battery life then you will need to keep your frequency the same or lower to notice a difference. If you are overclocking (increasing current) and undervolting then your P stays the same so the user ends up feeling the battery life to be the same or worse.
Facundo
Are there any standard or over volt kernels available so we can test this theory? It seems as though all the kernels available are UV.
Sent from my SCH-I500 using XDA App
would you like a standard voltage kernel to test?
Personally I see worse battery life on UV kernel. My usage mostly equals to dumb phone, with email sync and moderate web browsing.
I would change formula to I = V/R, which will read as current is directly proportional to voltage and inversely proportional to resistance. That makes obvious that reducing voltage we decrease current. However one point to note here is that this law is for PASSIVE conductor, which is obviously not our case. I would not speculate further, because we do not know what king of power conversion happens. It might simply turn out that conversion is not efficient at lower voltages. Google desktop power block certifications/efficiency to see whet I mean.
I compiled some kernels so you folks can play with it. I SERIOUSLY doubt you will get better life with my stock voltage vs. undervolt, but give her a shot.
Undervolted
Voodoo
http://adrynalyne.us/files/kernels/adryn_test2_0116_fascinate_voodoo5.zip
Nonvoodoo
http://adrynalyne.us/files/kernels/adryn_test2_0116_fascinate_novoodooo.zip
Standard voltage
Voodoo
http://adrynalyne.us/files/kernels/adryn_sv_0116_fascinate_voodoo5.zip
Nonvoodoo
http://adrynalyne.us/files/kernels/adryn_sv_0116_fascinate_novoodoo.zip
I'm giving the SV Voodoo kernel a try right now.
Sent from my Samsung Fascinate running BH3.0, DL09, and Voodoo5 using SwiftKey and Tapatalk
I thought about this as I thought about power lines. They use super high voltages to reduce the amount of power loss through the lines.
Anyways, sounds good, I'll test it out. I'd have to get a baseline. I guess I'll charge my phone right now and test out the regular voltage.
I'll let you guys know tomorrow the differences tomorrow.
In all honesty, I don't ever feel that I get more juice out of unvervolt kernels and I've been using all kinds of kernels since the release of MT3G.
Thanks for the standard voltage kernel!
I do appreciate you efforts in continually optimizing these, having a baseline to compare to just makes it all the more wonderful.
I will give the SV (standard voltage) a day or so of testing and then compare the UV against to make the test fair. With ten minutes of use ^^, it is already a great contender for my daily driver. I had gone back to 11/29 from 12/30. 11/29 was a terrible pairing with DL09; my GPS was unusable.
$ busybox md5sum ad*.zip
aea1047f3b2d33e759064d47cc8cac27 adryn_sv_0116_fascinate_novoodoo.zip
Works great!
Swyped w/ XDA App. When in doubt, mumble.
I wonder if android has battery test application, just to be put everything in the same play field? It's kind of pointless to compare subjectively.
Well, I tried to be objective with this test I just did.
Here were my conditions:
Charge to full, write down the time it was at full charge which wasn't 100%.
Let it sit for one hour.
Write down the charge.
SV Conditions
Starting charge 99%
Ending charge 97%
UV Conditions
Starting charge 98%
Ending charge 96%
The results...
SV - 3% discharge / hour
UV - 2% discharge / hour
Errors analysis:
There are several issues with this test because they were not even at the same charge at the start. Batteries have their maximum charge at 100%, and the rate of decrease is not a linear decrease. More testing is needed to compare the results.
Also the duration is not long and other factors have not been considered such as background applications refreshing on their own. I will have to test for 8-10 hours of each at idling tomorrow to get an accurate measurement.
Currently, I'm still on the UV kernel and I'll publish my results tomorrow of the UV over the 10 hour period.
Then I'll try to not use my phone throughout the day and test the SV.
It would be nice if someone could test the SV and UV with moderate usage and write down the initial charge, final charge, and the duration between the measurements. And another using heavy usage.
Thanks.
RacerXFD said:
SV Conditions
Starting charge 99%
Ending charge 97%
UV Conditions
Starting charge 98%
Ending charge 96%
The results...
SV - 3% discharge / hour
UV - 2% discharge / hour
Click to expand...
Click to collapse
Im confused with your math here...
Yeah, your math is off.....
Sent from my SCH-I500 using XDA App
RacerXFD said:
So this is a development idea...
I thought about this the other day and realized that under volting could be causing my battery to die quickly...
Here's why.
V = I * R
Where v = volts, I = amps, R = ohms.
P = V * I
Where P = (power)watts
I know some of you are going to think that this doesn't belong in development, but here me out here.
So if the processor uses 1.5 Watts and we decrease the voltage, this means that the processor needs to increase current to maintain that power. This equates to reduced battery life.
I'm just suggesting that undervolting may be causing the low battery life. If you know better feel free to tell me I'm wrong, but please explain the mechanics of what is going on not just your theory.
Click to expand...
Click to collapse
I'm an electrical engineer, and none of this makes any sense. V=IR is for current and voltage going through/across a constant resistor. Transistors are not constant resistors. The current through a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), the type of transistor that is in basically all ICs, is always in positive relation to the voltage, at least for the purposes of this basic explanation. Decreasing the supply voltage, which is you can consider to be the VGS of a transistor for a simple analysis, is always going to decrease the current as well. Thus, depending on the range of operation of the MOSFET, decreasing the voltage will also decrease the current and thus power will decrease more than linearly. Less current means that the transistors will charge and discharge capacitances slower, and that's why you need voltages for higher clock speeds and overclocking IN GENERAL. Device physics is really weird.
Now, someone else was saying that maybe because you undervolt it less current goes through which means it needs to spend more time in a higher clock state. This is completely false, the current going through it has nothing to do directly with the amount of work done. Yes, you need more current for faster clock speeds, but at a given clock speed, it doesn't matter how much voltage or current there is and how fast the individual parts of the circuit work, as long as the longest delay in any part of the circuit is less than the clock rate. If it's longer than the clock period, then your circuit is no longer going to function and you'll have instability and crashes, but there is a bit of wiggle room designed into these circuits because each chip can be different. That's why you can overclock or undervolt a CPU, because obviously if it was designed to run at the fastest clock speed possible, any little variation in supply voltage, temperature, manufacturing process/lithography (which is very common) would cause your CPU to completely not function. You have to design your circuits to be tolerant of some amount of error from many sources (even cosmic radiation in some cases), otherwise it won't just be slow, it won't function at all. Logic circuits are clocked to synchronize data going through the circuit, and if the timing constraints aren't always obeyed you'll get wrong answers which would probably crash your OS. Undervolting will never cause the CPU to do less work in one clock cycle, unless you undervolt it too much, in which case things will likely blow up in your face.
Sorry for the wall of text, but hopefully this will clear up some stuff. And in the future, please stick to what you're good at and don't try to speculate things based on one formula that you heard sometime in physics while you were half asleep, or something some CSR told you to get you to shut up. Believe it or not, the people who are designing CPUs and writing/modifying kernels and operating systems actually know what they're doing and you're not going to suddenly realize that they're going about their business wrong because of something you learned in high school.
Edit: One other thing. The calculation of percentages of battery life is a bit of guesswork on the side of your phone, trying to determine via statistics what a voltage level means in terms of percentage of battery life. Battery voltages don't drop linearly as you use them, and can be affected by many things, such as whether it's plugged in to the charger in particular. That's why you see a drop immediately when you unplug your phone, and why looking at 2-3% differences is completely meaningless. The better way to test would be to actually see how long you can use it with an equal amount of work being done on each voltage, which is hard to do in real life. Too many variables are present in today's smartphones, what with background tasks and data coming and going and the like. And wireless radios are a huge battery drain, especially when you're receiving a weak signal. I would advise people to just carry a charger or usb cable with them and top up your battery when you need to rather than worry so much about small differences in battery life. You'll save on a lot of stressing .
Thanks for the explanation. I'm an aerospace engineer. I did have to take a few courses in EE, but nothing to your level. So please let me know if I'm completely off on my testing.
I am pretty sure that the Devs know what they're doing, but I was getting tired of my low battery life and I was willing to test this theory of mine out for them. Again, seriously if I am completely out of the park in terms of this testing, let me know. And I'm ok with being called stupid as long as you teach me what I did wrong...
Yea, I completely forgot how with transistors, the math regarding voltage is handled differently than through a resistor. Are you telling me that the battery life will not be different between standard voltages and under voltages?
EDIT: I understand what you're saying about lowering voltage lowers current because the current has a linear relationship with the voltage in a MOSFET chip. Thanks, I had to read that like 5 times to understand and remind myself.
This is a complete waste of my time at this point because I know what's going on, but I wish to share my results anyways...
Ok here's where I got with the testing since last night. I realize that battery life is nonlinear. But i figure this is better than nothing.
But I did complete 8 hour test of SV at idle.
Starting charge percentage 94%
Ending charge percentage 82%
Which results in 1.5%/hour discharge rate at idle.
Will do the undervolt today. I'll document that in roughly 8 hours.
Is there a negative effect of setting the clock speed lower while screen off? Aside from running really labor intensive tasks?
It just seems like a great way to save battery to me. Right?
The only negative is getting the phone to wake up fast enough when you get an inbound call.
The CFS kernel (which is widely used now) seems to be less able to come out of a deep sleep rapidly than the older "zanfur" OC kernel did.
IIRC, on the older "zanfur" OC kernel, you could set the minimum scaling frequency to 19 Mhz - but with with the CFS kernel, you may need to use a minimum value of 122 Mhz or 245 Mhz.
Set the max scaling speed to 480 or 528 when sleeping. (The max frequency is only rarely used when the phone is sleeping - but you want the phone to pop out of it's low speed state quickly when you power up the screen, or experience an inbound call).
Thanks, Yeah I usually set the max to 480 while sleeping and 480 as min while awake. Battery seems good there.
Originally I was using SetCPU but I have switched to CPUBoost. Most all the kernels in the past few roms I have used are made by conap and he is also the creator of CPUBoost, so I figured they would integrate really well.
Also if I enter anything above the 800 range the phone will have random reboots throughout a few different roms I've tried.
As a note, if I remember correctly, if you have a kernel/ROM that supports the smartass governor, you should be able to use it and not need to have a profile set to underclock while the screen is off, or really need to underclock at all, as I believe it determines for you how much CPU is needed and sets the clock speed accordingly, simply abiding by your max and min speeds you set. Since less CPU is needed when the screen is off, it will automatically adjust accordingly. However, this is just something I've read around the forums, so don't take my word for it
Pokelover980 said:
As a note, if I remember correctly, if you have a kernel/ROM that supports the smartass governor, you should be able to use it and not need to have a profile set to underclock while the screen is off, or really need to underclock at all, as I believe it determines for you how much CPU is needed and sets the clock speed accordingly, simply abiding by your max and min speeds you set. Since less CPU is needed when the screen is off, it will automatically adjust accordingly. However, this is just something I've read around the forums, so don't take my word for it
Click to expand...
Click to collapse
Thanks for the info, I didn't know that. I will assume that's more or less accurate unless Conap or bftb0 chime in.
Pokelover980 said:
As a note, if I remember correctly, if you have a kernel/ROM that supports the smartass governor, you should be able to use it and not need to have a profile set to underclock while the screen is off, or really need to underclock at all, as I believe it determines for you how much CPU is needed and sets the clock speed accordingly, simply abiding by your max and min speeds you set. Since less CPU is needed when the screen is off, it will automatically adjust accordingly. However, this is just something I've read around the forums, so don't take my word for it
Click to expand...
Click to collapse
roirraW "edor" ehT said:
Thanks for the info, I didn't know that. I will assume that's more or less accurate unless Conap or bftb0 chime in.
Click to expand...
Click to collapse
Well, I suppose it could be said that the whole point of any rate governor is to reduce overall power consumption without markedly affecting the user's perception of "responsiveness" or "speed" - however they go about defining those metrics.
OTOH, because there are - what - five different scaling governors available, it is apparent that people have found their own reasons to create new scaling governors; presumably that arose from a dissatisfaction with the behavior of the available scaling governor - or, that different users have differing application workloads, and so they prefer one governor over another.
As Pokelover980 suggests, you could just hand a given rate governor a fixed set of limits (min/max), and be done with it.** For folks that have the time and desire to experiment, I would suggest that: pick a governor and a min/max clock rate and run that way for 2-3 days - no profiles at all. Then pick a different governor with the same min/max clock rate and run that way for another 2-3 days, and see how it goes - maybe not in battery life, because that's hard to measure in a repeatable way, but at least to see if any problems occur coming out of sleep.
Is the "smartass" governor better than all the rest of them? I don't really know. I used it for a little while, but found something I didn't like about it. (But don't take that as conclusive about anything; I doubt that I was doing disciplined testing when that happened). I tend to use either "interactive" or "ondemand", and don't have a strong preference for one over the other.
There probably is some value in keeping things simple. I think that I mentioned before that at one point (back when the CFS kernels were still in a state of flux) I was convinced that using setCPU was exacerbating problems with lock-ups I observed (once every couple of days). Again, though - that was really only my suspicion; I can't really prove it.
bftb0
** I suppose that folks that insist on extreme levels of overclocking ought to use either an overtemp profile or some other means to monitor temperature so that they don't cook their phone.
I Installed SetCPU on the wifes Eris. The smartass governor on CM7 will max out the cpu (to your preset max) if needed. I dont think the smartest thing to do is max out the cpu at 15% batt life. I have 5 different profiles set. One for screen off, charging, < 50%, < 30%, <10%. I use interactive governor vs smartass. Her phone is pretty responsive and I dont hear about issues with it not waking up. Battery life has also increased quite a bit.
As I understand solution for "998 MHz with screen on" bug is found: http://forum.xda-developers.com/showthread.php?t=1225411&page=17#post16944722
We need to replace only one governor.
I don't want to play with different ROMs and kernels and I'm looking for simplest solution.
Is it possible to compile it as a module ("ondemand_mod" for ex.) and add it to stock ROM?
Or any other (simple) way?
Wrong section ...
Sent from my X10i using Tapatalk
Why wrong Section, this is Development to get the CPU Governor working correctly
Wolfbreak said:
Why wrong Section, this is Development to get the CPU Governor working correctly
Click to expand...
Click to collapse
Exactly, this is the right section for such request.
However, I can't help but wonder: is this really a "problem"?
No offence to anyone, but I find that the phone is very snappy
when on max frequency... The big problem for me, would be if it
didn't go into Deep Sleep immediately after turning the screen off
and stayed at min frequency for an extended period.
When the screen is on (aka using the phone) I'd like it to be as FAST
as possible. That's the reason I use the minmax governor.
Anyway, again, I don't mean to argue with anyone, I am just
presenting my point of view.
My_Immortal said:
However, I can't help but wonder: is this really a "problem"?
No offence to anyone, but I find that the phone is very snappy
when on max frequency... The big problem for me, would be if it
didn't go into Deep Sleep immediately after turning the screen off
and stayed at min frequency for an extended period.
When the screen is on (aka using the phone) I'd like it to be as FAST
as possible. That's the reason I use the minmax governor.
Anyway, again, I don't mean to argue with anyone, I am just
presenting my point of view.
Click to expand...
Click to collapse
Yes, it's really problem.
Higher frequency - higher power consumption. Moreover - with higher frequency CPU used with higher voltage so consumption is even more higher. So at 998 MHz CPU eats about 5 times more battery than on 246MHz.
With properly tuned governor I don't feel any real lags or slowdowns.
And, when screen is on CPU load is usually is lower than 20% at full frequency. So I don't want to waste my battery.
As I see it's possible to compile and use governor as module.
Could someone compile it? And assemble as xRecovery package?
Or point me where to read about compiling for arm, where to get tools and so on...
Karlson2k said:
Yes, it's really problem.
Higher frequency - higher power consumption. Moreover - with higher frequency CPU used with higher voltage so consumption is even more higher. So at 998 MHz CPU eats about 5 times more battery than on 246MHz.
With properly tuned governor I don't feel any real lags or slowdowns.
And, when screen is on CPU load is usually is lower than 20% at full frequency. So I don't want to waste my battery.
Click to expand...
Click to collapse
The thing is, on 245 MHz, you can't get any kind of decent performance.
Try this: set the minimum and maximum CPU frequency with SetCPU to 245 and attempt to use the phone normally.
Also, you might be right about voltage, but if the CPU is forced to work on lower freqs when it actually needs higher, there's definitely stress and increased battery consumption.
My phone lasts for more than 24 hours and it's always at max frequency when the screen is on. No lag, no freezes, no drain.
I do agree that the ondemand governor might not function as expected but I fail to experience the actual problem. That might be just me though.
Xperia X10i via Tapatalk
My_Immortal said:
The thing is, on 245 MHz with high load, you can't get any kind of decent performance.
Try this: set the minimum and maximum CPU frequency with SetCPU to 245 and attempt to use the phone normally.
Also, you might be right about voltage, but if the CPU is forced to work on lower freqs when it actually needs higher, there's definitely stress and increased battery consumption.
My phone lasts for more than 24 hours and it's always at max frequency when the screen is on. No lag, no freezes, no drain.
I do agree that the ondemand governor might not function as expected but I fail to experience the actual problem. That might be just me though.
Click to expand...
Click to collapse
There is no need to work on 245MHz as proper governor rise frequency automatically when it's necessary.
And really no stress for CPU to work an low frequency at full load. Moreover - CPU will consume more power at 500Mhz with 45% load than at 250Mhz with 95% load.
Sometime I use phone for navigation - long time with screen on and very low load. In this scenario battery drains very fast.
And last one - I like to have everything working properly. In case that I'll really need high frequency all the time I'll use other governor. I just want to have a choice.
I need a simple solotion for this too..I use z kernel and I found that Thego2s kernel fixed this problem..I was going to flash that kernel but think that has a bug and stoucks on logo ..can some one sayas a simple way?
Yes, I think a lot of people would prefer to use just small and simple fixes rather than replacing the whole kernel with a lot of nice but (personally) unnecessary features.
I am waiting for developers to release a fix for this problam
As far as I've seen, Everybody in this forum says that clocks 480 or below have the same voltage, so setting min clock as 480 is enough and no difference in terms of battery consuming even if you set it to 245.
I know it is right about voltage(I searched about that myself), but does same voltage means same energy consumption?
you guys must already know that higher clock makes more heat, so where does the heat come from? it's from your battery!
(from what I learned from school E=V^2*t/R where E is energy, V is voltage, t is time and R is resistance so there's another fact for electric energy other than voltage and time)
So I think you should set the min freq to 245 unless you feel uncomfortable for its low responsiveness.
is there anything wrong in my theory?
For this you can't depend on equations etc, it has to be tested each by everyone of us to feel which one is better for us and which is more battery saving. Personally I felt 245mhz drains a bit less than 480mhz however it is less responsive. I remember i saw in forums about this(althought another device) and it was one heck of a debate, but the conclusion was each and every person has to test for themselves.
And the wakes ofcourse, the amount the kernel wakes per second.
Deep sleep **** counts also...
If you have wakelocks, set as low as you can, if you don't, use 480
Sent from my LG-P500
You're right about energy consumption,i've been with extreme-cpu overclocking(on pc) for quite some time and a higher clock on same voltage will indeed consume more+more heat. But here like you've seen ^ it's related to wakelocks and if there are any apps running, if deep sleep is ok and stuff so there are many factors.
Best is to try and see wich fits you best regarding performance/battery/stability also it depends on the guvernor if you have a snappy one it will push your cpu to max even if you surf between screens
This is one of the biggest "not solved point" about O.1 configuration....
To adress this and other "open point" i developed an app for logging resources consumption
more info here:http://forum.xda-developers.com/showthread.php?t=1505950
Did a test with a cpu benchmark (simple thing to test how fast it does some things)
Did those in powersave governor:
122MHz
>10000ms (took a minute to do the test)
480MHz
~1900ms
Also did in 245, and I got 4392ms, and this is very good
Sent from my LG-P500
Hi Guys,
I am a noob here. I have never used a android phone before, not even a iPhone - so basically no smart phones.My first smart/android phone would be Nexus 4 which would be coming tomorrow.
I have been reading threads to understand andriod architecture and believe have understood to certain extent.
I have a question in clocking the CPUs and Voting.
As I understand, we have 3 states -Max, Min and Sleep for a single CPU core
Max - The frequency (clock speed) which CPU executes or maximum speed which CPU sends signals to its components and get the response back. This would be used when the system is on - which means when user is doing some process.. like texting, video chat, gaming (this case GPU is also involved) etc.
Min - This would be for background process when the user/phone is idle - that when screen is off (eq - gmail sync, facebook sync etc..)
Sleep - Screen off and no background process , the core will be in sleep.
And the battery level will be directly propotional to speed of CPU with respect to the volting.
Now lets say there is a single core processor in a phone which can clock upto 1.5GZ. and the stock kernel comes up with Max - 1.3GZ and MIN -0.5 GHZ.
Question is abt overclocking minimum frequency
1. why not overclock the Mn frequency to 1.3Ghz? because the backgroundprocess would be fast and phone/core will be sleeping after that,
which means process consumes more battery at that particular time but overall baterry should be efficient as there would be more sleeping time.
2. About volting, so far I have not seen min and max volting. So is there only one voltage/power drawn for max and min CPU speeds by CPU?
Please correct me if any of my statements is wrong.
Appreciate your help,
Thanks,
Franklin B.
Overclocking the minimum frequency to 1.3ghz would probably decrease your processor's life if you use your phone too much but I have been actually increasing my phone even 200mhz more than it was in stock ROMs, i've been using my device for more than 2 years and it still works perfectly. Finally, it all depends on how much your phone is good.
I also decreased the cpu min and max frequency when phone sleeps to 256 mhz which decreased a lot battery consumption.
Hope i helped !
Don't forget the THANKS button
1.you can but your battery life will be drastically reduced! There is a good amount of time after the screen is off and before the phone sleeps! So if over clock the min to 1.3Ghz, the processor will be running at 1.3Ghz till it goes to sleep! But if that's what you want you can do that!
2 . I'm not so sure about this topic either but I think the processor operates at a particular voltage and I could be wrong!
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Thank you Guys
Franklin Bernard said:
1. why not overclock the Mn frequency to 1.3Ghz? because the backgroundprocess would be fast and phone/core will be sleeping after that,
which means process consumes more battery at that particular time but overall baterry should be efficient as there would be more sleeping time.
2. About volting, so far I have not seen min and max volting. So is there only one voltage/power drawn for max and min CPU speeds by CPU?
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Hi, I received your PM. I agree with the guys about the heat issues, longevity, and battery life etc. The answer to your question #2 will help you better understand things.
In all kernels, there are frequency/voltage scaling tables. For every frequency step (clock speed) in the table, it corresponds to a specific voltage. It gets a bit more complicated than this of course, but that is the basic way things are setup in the kernel. The higher the frequency, the higher the voltage is required to be to keep the CPU (or GPU, bus, RAM etc.) stable at a given clock speed. The more voltage, the more current, and the more heat is generated. The longer you stay at higher clock speeds/voltages, the better the cooling system you need to have. Supply regulators are defined to feed the core and rail voltages so that the processor can live in a happy environment no matter what it is being asked to.
As far as power consumption, it's all about getting a unit of work done in a timely/efficient fashion using the least amount of power consumption. If the phone is sleeping, the word "timely" takes on a different meaning so then it is mostly concerned with power consumption and getting the background tasks completed effectively without having the phone experience the sleep of death (SOD). What you are talking about is the theory of "race to sleep" so that the work can be done quickly and the phone can go back to sleep where it uses the least amount of power (clocks actually turn off during deep sleep and cores are turned off). However, there is a happy medium to this theory and heat and battery consumption are the main enemies. Heat can also rob efficiency, more current is required when a circuit heats up. The more a phone wakes up to do syncs for email, apps, social networking, missed calls etc., that work can stack up throughout the day. The question comes down to how can the device get this work done using the least power and keep the device cool. On the N4, the lowest frequencies can use ~700-800mV per core while the highest frequencies can use ~1100mV. There is a drastic difference in the amount of heat generation between this range.
I think this should give you the general idea and maybe more that you wanted to know! Here are some links to check out if you are interested. Google and you will find many many more articles and research papers.
http://en.wikipedia.org/wiki/Voltage_and_frequency_scaling
http://atrak.usc.edu/~massoud/Talks/Pedram-dvfs-Taiwan05.pdf
Thanks a ton !!!