[Q] Switching off cores to save energy? - Nexus 4 Q&A, Help & Troubleshooting

Heya All. So far Im running a Milestone 1 (Single Core, 600Mhz) - so Im used to my phone being kinda slow.
My question would be if you could simply switch of 1 - 3 cores on the nexus or simply tell the OS to not utilize them.
In my theory the phone should still be fast enough to handle most of the tasks, but saving battery.
Question 1: Do you think that's possible?
Question 2: Do you think that would save battery?
I guess it would save battery, although the last working core would have to do more work.
Any answers / ideas are welcome =)

Android does that by him self.
Also every (4) cores runs on 15-20% eats less power than one core to maxs.
Sent from my LT26i

Yeah, but don't you think that 1 core at 100% is better in terms of efficiency than 4 cores at 25% ?

Titan2189 said:
Yeah, but don't you think that 1 core at 100% is better in terms of efficiency than 4 cores at 25% ?
Click to expand...
Click to collapse
No, the opposite is true. It is more efficient to power 4 cores at 25% than one at 100%.
Of course efficiency depends on the SoC used, in this case the S4 is highly efficient.

Titan2189 said:
Yeah, but don't you think that 1 core at 100% is better in terms of efficiency than 4 cores at 25% ?
Click to expand...
Click to collapse
Basically CPU can process only one task at time. If you have four CPUs (4 cores) you can process 4 task at the same time.

Titan2189 said:
Heya All. So far Im running a Milestone 1 (Single Core, 600Mhz) - so Im used to my phone being kinda slow.
My question would be if you could simply switch of 1 - 3 cores on the nexus or simply tell the OS to not utilize them.
In my theory the phone should still be fast enough to handle most of the tasks, but saving battery.
Question 1: Do you think that's possible?
Question 2: Do you think that would save battery?
I guess it would save battery, although the last working core would have to do more work.
Any answers / ideas are welcome =)
Click to expand...
Click to collapse
1. Yes, technically speaking it's possible - but you won't be able to do it with stock ROM.
2. No. I doubt that. If you use one core and the core gets overheaded due to high load, then it's the opposite of energy saving. Don't bother tinker to much with core scheduling, since such tasks are buried deep in the US kernel. There've been tons of research putting into how to utilize multicore systems effectively, and as a user I would advise against tinkering with such low-level management. My point is, are you sure you can do it better than hundreds (or thousands) engineering hours spending on the kernel?

Epic
This is exactly what I'm gonna do.
I can live with a wee bit of slowness as long as the battery live is long enough.
So I'll undervolt and underclock as much as possibe... 800 mhz are sufficient for me.
And the ability to clock up whenever I need to...

I was planning to underclock too - probably to around 1Ghz.

Underclocking is different from core scheduling. Under locking definitely saves battery , though it comes with performance trade off. However, disabling cores randomly WILL NOT save battery and probably do the opposite.
I guess some people can tinker the kennel to try optimize the scheduling. But that's the job of developers, I'm against users venturing into such areas
Sent from my Galaxy Nexus using Tapatalk 2

You have to be careful though with underclocking...
Although your CPU is slower, it also takes more clock cycles to complete! So don't go throwing it into 200Mhz range lol.
In the overclocking world though, you can OC a LOT higher on one core, but that's about all you get from disabling other CPU's

Related

Overclocking

Can over clocking the phone can burn or cause damage to the hardware except excess battery usage and does overclock an 1ghz processor to 1.5 will really give a boost or its just a gimmick
Sent from my Desire HD using XDA App
Excessive overclocking really did damage your hardware, depends on the quality.. Overclocking from 1.0ghz to 1.5ghz really give a performance boost, in benchmarking.. In real life, only noticeable in process hungry apps, such as 3d games.. Gimmick? Well, if its a gimmick, it won't give any sudden resets or lock ups.. The processor have a safety switch if the temperature increase because of oc'ing.. If it's to hardcore, for example, 1.0Ghz to 1.8Ghz or even 2.0Ghz, for sure you processor will overheat and lock ups.
Well, mine running at 1.5Ghz, no lock ups or whatever..
SAPPH1RE said:
Excessive overclocking really did damage your hardware, depends on the quality.. Overclocking from 1.0ghz to 1.5ghz really give a performance boost, in benchmarking.. In real life, only noticeable in process hungry apps, such as 3d games.. Gimmick? Well, if its a gimmick, it won't give any sudden resets or lock ups.. The processor have a safety switch if the temperature increase because of oc'ing.. If it's to hardcore, for example, 1.0Ghz to 1.8Ghz or even 2.0Ghz, for sure you processor will overheat and lock ups.
Well, mine running at 1.5Ghz, no lock ups or whatever..
Click to expand...
Click to collapse
My phone is running quite happily on 1.84Ghz.No lock ups or overheating.
ttav said:
My phone is running quite happily on 1.84Ghz.No lock ups or overheating.
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Click to collapse
Good for you though.. Mine can only be stable at 1.7Ghz.. At 1.8Ghz, only about couple of mins gaming, and then hang till forever..
niks_5in said:
Can over clocking the phone can burn or cause damage to the hardware except excess battery usage and does overclock an 1ghz processor to 1.5 will really give a boost or its just a gimmick
Sent from my Desire HD using XDA App
Click to expand...
Click to collapse
You will barely notice the difference in most circumstances. Even if your phone runs fine at 1.5 or 1.8 ghz it will probably reduce the life of the chip over a prolonged period.
-----
Someone Swyped my idea.
I think it will give minor boost at the cost of burning your hardware
Sent from my Desire HD using XDA App
it will help in cpu intensive tasks, that which require lots of calculations, math stuff, 3d drawing done via cpu, faster cpu, better...
in other tasks, don't even bother, there are lots of other things far slower then cpu.
downside, heating, battery drain, increased rate of damage..!
Im using SetCPU for saving battery life. Set the cpu for 384 while screen is off. Noticed quite a difference.
OP, your asking if a overclocked cpu will give a better performance or if it's a gimmick? Really??
Of course it will give you better performance, that goes without saying but the question is, are you willing to sacrifice battery life? The chip will most probably last for years and years if overclocked but 1 thing that kills chips is heat and volts.
I only overclock when I need to and when I'm done I go back to how it was, usually.
My phone is fast enough at 1GHz, dont need overclocking, all games and apps goes fine fine
Most OC kernals are also undervolted anyway so I wouldn't worry about it
to be honest, i use mine with "underclocked" at 800mhz, trying to get at least a half-hour of battery life... i don't see the point in overclock a 1ghz processor, imo, even with a speed gain, the bad side effects easily override the good ones...
i truly believe that overclock my old milestone was the main cause of the problem that happens after...
thiagodark said:
to be honest, i use mine with "underclocked" at 800mhz, trying to get at least a half-hour of battery life... i don't see the point in overclock a 1ghz processor, imo, even with a speed gain, the bad side effects easily override the good ones...
i truly believe that overclock my old milestone was the main cause of the problem that happens after...
Click to expand...
Click to collapse
I'd look at other reasons for your battery life, if it's really that bad.
I'm running at just a touch above 1GHz with no side affects what so ever and get 24+hrs with heavy use, 30+hrs with moderate use and 40+hrs with light use, and that's never turning wifi / 3G off unless I'm in bed when I switch to 2G.
At 1GHz the OCUV kernal I have installed uses less voltage than stock kernal at stock speeds so in theory it's actually safer.
It's not that bad, but it's not so great as yours too. I got about 16hrs with 'hard' use, what is enought most time, but sometimes i get in home with the blinking orange led. Quite annoying...
I try my best to improve the battery life, but i was becoming a battery freak, or something like that, always checking currentwidget...
I get 3 or 4ma at stand by, what is considered normal, i guess... and always use full brightness, hate to use anything bellow...
Sent from my Desire HD using XDA App
thiagodark said:
It's not that bad, but it's not so great as yours too. I got about 16hrs with 'hard' use, what is enought most time, but sometimes i get in home with the blinking orange led. Quite annoying...
I try my best to improve the battery life, but i was becoming a battery freak, or something like that, always checking currentwidget...
I get 3 or 4ma at stand by, what is considered normal, i guess... and always use full brightness, hate to use anything bellow...
Sent from my Desire HD using XDA App
Click to expand...
Click to collapse
Full brightness is your problem. I bet it uses like 70% of the current while you use your phone.
going up to 1.8GHz still running stable, thats crazy man!
smurcoch said:
Full brightness is your problem. I bet it uses like 70% of the current while you use your phone.
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Click to collapse
Yep, you are correct, it's using about 75% of the battery...
Sent from my Desire HD using XDA App
Any performance boost on 1.8 ghz
Sent from my Desire HD using XDA App

Kernels, number of cores, deep sleep

Hi, I am trying a lot of different modded kernels for my brand new Nexus 4. However, due probably to the fact that I am not competent enough to look at the code of the patches they apply I have difficulties in understanding some technical differences between them. In particular:
1) It seems to me that some kernels use only some of the four cores of the processor. Namely, I have noticed that Franco kernel uses only two cores, while Trinity hotlplugs all of them when needed. Is there some evidence in support of one or the other choice? How the other kernels behave under this point of view?
2) There seems to be a huge difference for what concerns the time spent by my device in so-called "deep sleep". E.g. when I use Trinity the device, looking at the stats, seems to stay in deep sleep for almost all the time in which the screen is off, while in Franco this happens for a shorter time and in Matrix kernel almost never. However, this seems to have a negligible impact on battery life: e.g. with Matrix the processor is most of the time at the lowest frequency instead of deep sleep, but I get excellent battery life nonetheless. So I wonder if I should care about deep sleep at all.
Thanks in advance for any clarification.
patroclo7 said:
Hi, I am trying a lot of different modded kernels for my brand new Nexus 4. However, due probably to the fact that I am not competent enough to look at the code of the patches they apply I have difficulties in understanding some technical differences between them. In particular:
1) It seems to me that some kernels use only some of the four cores of the processor. Namely, I have noticed that Franco kernel uses only two cores, while Trinity hotlplugs all of them when needed. Is there some evidence in support of one or the other choice? How the other kernels behave under this point of view?
2) There seems to be a huge difference for what concerns the time spent by my device in so-called "deep sleep". E.g. when I use Trinity the device, looking at the stats, seems to stay in deep sleep for almost all the time in which the screen is off, while in Franco this happens for a shorter time and in Matrix kernel almost never. However, this seems to have a negligible impact on battery life: e.g. with Matrix the processor is most of the time at the lowest frequency instead of deep sleep, but I get excellent battery life nonetheless. So I wonder if I should care about deep sleep at all.
Thanks in advance for any clarification.
Click to expand...
Click to collapse
1) Franco kernel doesn't only use two cores. You can select 2 or 4 cores and hot plug via his app or script.
2) yes you should care about deep sleep, of anything it will provide batter idle battery life by a small margin
Sent from my Nexus 4 using Tapatalk 2
Vanhoud said:
1) Franco kernel doesn't only use two cores. You can select 2 or 4 cores and hot plug via his app or script.
2) yes you should care about deep sleep, of anything it will provide batter idle battery life by a small margin
Click to expand...
Click to collapse
Thanks for your reply. About 1), I meant to say that it uses two cores by default. What is the advantage in being restrained to use only half the power at disposal instead of using time by time what is needed?Am I right in thinking that in this way always the same two cores are used while the two others stay virgin? Or is there some kind of rotation, so that in each moment at most two are used but not always the same two?
patroclo7 said:
Thanks for your reply. About 1), I meant to say that it uses two cores by default. What is the advantage in being restrained to use only half the power at disposal instead of using time by time what is needed?Am I right in thinking that in this way always the same two cores are used while the two others stay virgin? Or is there some kind of rotation, so that in each moment at most two are used but not always the same two?
Click to expand...
Click to collapse
In franco kernel, hotplug is usually the default.
In hotplug mode, the default is set so that when there is minimal activity only the first two cores are active. This is to save battery and reduce heat i am assuming. When the cpu load increases, the 3rd and 4th core are activated to assist.this is also helpful in reducing the amount of times each cpu core turns on/off (i.e. hot plugging) because this action has an impact on performance. The first two cores stay on constantly until the load increased, then cpu 3 and 4 are activated . Once the cpu load falls down, 3/4 are turned off
when in dual core mode, yes only two cores are used period. You really cant even tell a difference when only using two cres, except for heavy gaming.
Quad core mode makes all the cores active all the time, best for gaming
Quad isn't always needed...Many android apps aren't even multi threaded so having every core on is foolish.
Sent from my Nexus 4 using xda app-developers app
by default, the device hotplugs. itll use the number of cores it needs when it needs them. you can set yourself how many cores the device can use as a minimum(with root). i use trinity, and i usually set that all four cores are used all the time. i see slightly better battery life that way.
you will see better idle battery drain the better the device deep sleeps. btw battery life is all dependent on how you use the device. if youre one of those people that barely touch your device, and let it lay around for log periods if time, then a deep sleeping device would be beneficial to you. if youre a power user thats constantly using the device nonstop then it wouldnt make any difference to you. most of us fall in between these two types of users

Which rom has a good battery life?

Hey i tried many diffrent rom bui i can only get 2.5h SOT. Which kernel do you use and which rom to get the maximum battery life without lag?
Battery<----------------------------------->Performance
They are at opposite ends. If you want maximum battery life then there no way to avoid lag.
You can completely turn off 2 or 3 cores, leaving you with a single or dual core phone;
You can also underclock and undervolt the remaining cores, reducing power consumption even more.
This is very battery friendly (in theory), but, as I said, it will give you big lags.
I added a rom video review to the help thread. You might want to check it out.
obol2 said:
Hey i tried many diffrent rom bui i can only get 2.5h SOT. Which kernel do you use and which rom to get the maximum battery life without lag?
Click to expand...
Click to collapse
Sounds like you really need a new battery
GDReaper said:
Battery<----------------------------------->Performance
They are at opposite ends. If you want maximum battery life then there no way to avoid lag.
You can completely turn off 2 or 3 cores, leaving you with a single or dual core phone;
You can also underclock and undervolt the remaining cores, reducing power consumption even more.
This is very battery friendly (in theory), but, as I said, it will give you big lags.
I added a rom video review to the help thread. You might want to check it out.
Click to expand...
Click to collapse
Don't mean to troll, but can't help it. Turn a quad core cpu into a dual core? Really?!
Erm... ok.
thundastruck said:
Don't mean to troll, but can't help it. Turn a quad core cpu into a dual core? Really?!
Erm... ok.
Click to expand...
Click to collapse
Do you have any better ideas on how to increase battery life?
Cores need power to run. Turning them off is a completely logical option.
You really don't need all the cores for most tasks. You can browse Facebook, or whatever, just fine with only two cores.
I am currently running in dual-core mode with max cpu frequency at 1.2 GHz and it still is smooth.
GDReaper said:
Do you have any better ideas on how to increase battery life?
Cores need power to run. Turning them off is a completely logical option.
You really don't need all the cores for most tasks. You can browse Facebook, or whatever, just fine with only two cores.
I am currently running in dual-core mode with max cpu frequency at 1.2 GHz and it still is smooth.
Click to expand...
Click to collapse
I aldeady underclockt it to 1.2 ghz and undervolting it -625000 uV. Shut off to cores and use intellimm. I also under clock gpu to 320 mhz and under volt it 1 step down. I use zen with 1024 kb. Turn off android logger and zram. Use amplify, power nap, greenify and Max 700 mhz screen off. What I can do more?
obol2 said:
I aldeady underclockt it to 1.2 ghz and undervolting it -625000 uV. Shut off to cores and use intellimm. I also under clock gpu to 320 mhz and under volt it 1 step down. I use zen with 1024 kb. Turn off android logger and zram. Use amplify, power nap, greenify and Max 700 mhz screen off. What I can do more?
Click to expand...
Click to collapse
Nothing.
Test your battery. Or better yet, start thinking of getting a replacement or a new phone. With a 2 hour charge something seriously is wrong with your device.
My 3 year old S4-i9500 still comfortably gets through the day. Bought a brand new original battery 6 months ago. Smooth sailing. No under-volting, shutting off cores, under-clocking or any crap like that. Phone is custom rom'med and correctly so if I may add.
obol2 said:
I aldeady underclockt it to 1.2 ghz and undervolting it -625000 uV. Shut off to cores and use intellimm. I also under clock gpu to 320 mhz and under volt it 1 step down. I use zen with 1024 kb. Turn off android logger and zram. Use amplify, power nap, greenify and Max 700 mhz screen off. What I can do more?
Click to expand...
Click to collapse
lower values for read ahead cache are more battery friendly.
Also, bfq is considered more battery friendly too.
thundastruck said:
Nothing.
Test your battery. Or better yet, start thinking of getting a replacement or a new phone. With a 2 hour charge something seriously is wrong with your device.
My 3 year old S4-i9500 still comfortably gets through the day. Bought a brand new original battery 6 months ago. Smooth sailing. No under-volting, shutting off cores, under-clocking or any crap like that. Phone is custom rom'med and correctly so if I may add.
Click to expand...
Click to collapse
In two month I will get a new phone. I want to buy the lg v10 but don't know if it is worth or lg g4 / moto x style.
obol2 said:
In two month I will get a new phone. I want to buy the lg v10 but don't know if it is worth or lg g4 / moto x style.
Click to expand...
Click to collapse
Never heard of these models except for lg g4, which was crap imo.
thundastruck said:
With a 2 hour charge something seriously is wrong with your device.
My 3 year old S4-i9500 still comfortably gets through the day
Click to expand...
Click to collapse
You are aware that he said 2.5h SOT, "screen on time" ?
That means that after using it for an entire day or two, the combined time of the screen being on is 2.5 hours, and in my opinion that is not really bad.
The screen is always the culprit when it comes to power consumption, and in a phone with a battery that doesnt exeed 2000mah its just natural
that after about 2-3 hours of the screen being on the little battery is empty, and no ammount of undervolting will extend that significantly.
The only thing he can consider to increase SOT is a bigger battery, if he doesnt mind the bigger bulge at the back.
Backe888 said:
You are aware that he said 2.5h SOT, "screen on time" ?
That means that after using it for an entire day or two, the combined time of the screen being on is 2.5 hours, and in my opinion that is not really bad.
The screen is always the culprit when it comes to power consumption, and in a phone with a battery that doesnt exeed 2000mah its just natural
that after about 2-3 hours of the screen being on the little battery is empty, and no ammount of undervolting will extend that significantly.
The only thing he can consider to increase SOT is a bigger battery, if he doesnt mind the bigger bulge at the back.
Click to expand...
Click to collapse
Had no idea - never really cared what SOT stands for anyway! But thanks for clearing that up. Always had satisfactory battery life on my S4. The few times I didn't was when a rom on my phone went bad & subsequently had to flash another.
So if what you say is true regarding a day or 2 battery life, then what is this chump complaining about? Turning water into wine? :silly:
So @GDReaper idea is right!I currently am on crDroid and when I switch off 2 or 3 cores the phone is as fast as it was and the battery lasts a little bit longer..With normal charging it goes to full for about 1 hour and half and without using it the batttery lasts 1-2 days,using it lasts about 3 hours or 4.I flashed a new kernel and turned on fast charging on Kernel Adiutor,now the phone charges full for about 45 minutes and lasts same! I'm very happy with my battery bcs I haven't changed it since I got the phone!

4 cores stopped

Hi all,
I have cpu z installed and I'm not rooted. It generally uses all 8 cores but when I accidentally opened it I saw that it was only using 4 cores. I decided to restart and it is still using 4 cores. Is this normal because my g5 plus always uses all 8 cores.
Your in low power or battery saver mode... look at the battery symbol.. I can't remember if it kicks in at 5% or 15% battery automatically, then turns off when you connect the charger... It sometimes takes a few minutes for everything to kick back in. I would bet after getting a decent charge it was back to normal?
There is also a issue with Nougat at newer reporting CPU usage incorrectly even in rooted devices... been talked about a lot, something in the stock Moto firmware (or maybe that was a different Moto, I get them confused sometimes).
Ok thanks. Apparently cpu z was wrong.
the cores are reduced to 4 when u are on battery saver.
On thanks. The weird part was I didn't turn the battery saver.
DarthMaul14 said:
On thanks. The weird part was I didn't turn the battery saver.
Click to expand...
Click to collapse
It's automatic at a certain battery level by default.
Oh ok. Does the same thing apply for quad cores and hexacores.
DarthMaul14 said:
Oh ok. Does the same thing apply for quad cores and hexacores.
Click to expand...
Click to collapse
It will throttle them, although the exact implementation varies somewhat depending on the actual processor. littleBIG architecture tends to be that the BIG cores get shutdown, on more standard architecture like the SD625 they will get throttled to 50-75% of maximum speed, and others may just get a couple random cores disabled, it depends on the CPU and how Qualcomm/MediaTek/whoever engineered it.
Ok thanks!

Is it possible to overclock?

Hi there,
Is it possible to overclock the cpu and gpu?
If so how? Or which rom/kernel?
Running G model 4gb ram
Even if you can, it will chew the battery and heat up.
RobboW said:
Even if you can, it will chew the battery and heat up.
Click to expand...
Click to collapse
Not a problem as I would only be using it sometimes not permanently
Kendal21 said:
Not a problem as I would only be using it sometimes not permanently
Click to expand...
Click to collapse
in theory it is, we had a a kernel that OC'd the CPU way back then, but the SoCs on the Axons are probably low-binned - shutdowns and stuff like that are commonplace
But still, do you know what OC does to a phone? New phones are thermally constrained devices, starting from the snapdragon 800 series onwards. remember the sd805/810 disaster? Well...
If you run your phone at 100% load, it will run at max speed (1.56/2.15) for a very short time (say, 30 seconds), until the SoC reaches a specific temperature. After that it'll go down to a more manageable frequency, eventually going even further down or staying at 1.8 ghz, depending on your specific situation (the pink thermal blob might be bad).
That's why VR mode sets your cores at around 1.8 ghz, to keep them from going hot and lowering frequency even more. Sustained performance is better than burst performance on gaming.
Day to day usage is another matter, because more frequency won't mean thermal throttling when opening apps or unlocking the phone, beside the obvious battery usage
TL/DR: Be prepared to make your own kernel if you want to OC. It might not work

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