4S should disable one core most of the time

gladoscc

macrumors 6502
Original poster
Jul 13, 2011
295
40
Lots of people are having disappointing battery life, so I think the 4S should disable one core until an application requests it, or it is plugged in. This way, you should get more battery life than the iPhone 4.
 

SplicedBanjo

macrumors regular
Dec 13, 2011
109
0
Apple has stated that the A5 processor uses the same amount of power as the A4, even though it has two cores. I'm thrilled with the battery life of my 4S, and while I understand that some people have issues with it, I do not believe this would be a good solution.
 

aristobrat

macrumors G5
Oct 14, 2005
12,256
1,336
Lots of people are having disappointing battery life, so I think the 4S should disable one core until an application requests it, or it is plugged in. This way, you should get more battery life than the iPhone 4.
When I turn off the iMessage/iCloud features that seem to have my iPhone 4s connecting to 3G data way more than my iPhone 4 did, my iPhone 4s gets slightly better battery life than the iPhone 4. I don't think that's core related.
 

Carlanga

macrumors 604
Nov 5, 2009
7,013
1,291
that is not what is causing the bad battery life for people :roll eyes: ;)
 

/user/me

macrumors 6502
Feb 28, 2011
496
0
Lots of people are having disappointing battery life, so I think the 4S should disable one core until an application requests it, or it is plugged in. This way, you should get more battery life than the iPhone 4.
you should try killing apps that are running in the background. especially location services.
 

gnasher729

macrumors P6
Nov 25, 2005
16,599
3,220
Lots of people are having disappointing battery life, so I think the 4S should disable one core until an application requests it, or it is plugged in. This way, you should get more battery life than the iPhone 4.
That way, you wouldn't get any more battery life.

ARM processors don't give any power to parts of the processor that are not currently in use. There is no need to disable an ARM processor; just don't give it instructions to execute.

When there is some work to do, the most power efficient way to do the work is to use all cores, but at the lowest possible clock rate. Power increases with the square of speed, therefore two cores at half the speed use much less power than one core at full speed.
 

psonice

macrumors 6502a
Jul 22, 2005
968
0
Yes, it's usually most efficient to do the work as fast as possible and screw the battery hit, because then the work is done and the CPU goes back to sleep where it consumes near zero power. And I'm pretty sure the A5 DOES power down one core when it's doing light work. It'd be pretty silly if it kept both active when only one is in use.
 

GraphicsGeek

macrumors 6502a
Sep 19, 2008
533
0
you should try killing apps that are running in the background. especially location services.
The apps aren't running in the background. They're suspended or frozen. That's one of the biggest misconceptions about the multitasking tray. Those apps are your recently used apps and are not running. The first screen are the frozen apps and the rest are just the recently used. They're not using up extra battery. Reboot your phone. If those apps were supposed to be still running, they wouldn't be there after a reboot. After a while iOS kills them completely but they still remain in the tray.
 

aztooh

macrumors 6502a
Jul 5, 2011
678
0
The apps aren't running in the background. They're suspended or frozen. That's one of the biggest misconceptions about the multitasking tray. Those apps are your recently used apps and are not running. The first screen are the frozen apps and the rest are just the recently used. They're not using up extra battery. Reboot your phone. If those apps were supposed to be still running, they wouldn't be there after a reboot. After a while iOS kills them completely but they still remain in the tray.
Calling it the "multitasking tray" further confuses people. It's what you say in your next sentence, it just shows your recently used apps. Which are all 'suspended'.

Though some do still run, i.e. mapquest4mobile (and I'd assume all other navigation apps) and iPod or "music" now I guess just to name a couple.
 

JeffreyDJ

macrumors regular
Jun 26, 2010
130
0
The apps aren't running in the background. They're suspended or frozen. That's one of the biggest misconceptions about the multitasking tray. Those apps are your recently used apps and are not running. The first screen are the frozen apps and the rest are just the recently used. They're not using up extra battery. Reboot your phone. If those apps were supposed to be still running, they wouldn't be there after a reboot. After a while iOS kills them completely but they still remain in the tray.
Start up a navigation application and leave it running in the background.

While what you said is mostly true, they can activate system processes that remain active in the background.

JJ
 

Intell

macrumors P6
Jan 24, 2010
18,883
372
Inside
The apps aren't running in the background. They're suspended or frozen. That's one of the biggest misconceptions about the multitasking tray. Those apps are your recently used apps and are not running. The first screen are the frozen apps and the rest are just the recently used. They're not using up extra battery. Reboot your phone. If those apps were supposed to be still running, they wouldn't be there after a reboot. After a while iOS kills them completely but they still remain in the tray.
This is correct.

Start up a navigation application and leave it running in the background.

While what you said is mostly true, they can activate system processes that remain active in the background.

JJ
App developers can choose to use one of 7 multitasking APIs that are provided by iOS. When using one of these APIs, their own application transfers its processes to iOS' API sub-structure. The app is then frozen until it becomes the active app or it's killed by iOS to free up ram.
 

JeffreyDJ

macrumors regular
Jun 26, 2010
130
0
App developers can choose to use one of 7 multitasking APIs that are provided by iOS. When using one of these APIs, their own application transfers its processes to iOS' API sub-structure. The app is then frozen until it becomes the active app or it's killed by iOS to free up ram.
Exactly. And while the poster above may not have expressed it technically correctly, apps that activate and run those processes in the background can use battery more quickly. Which is why that poster recommended force quitting applications specifically those that use location services... Sigh.
 

SporkLover

macrumors 6502
Nov 8, 2011
498
1
That way, you wouldn't get any more battery life.

ARM processors don't give any power to parts of the processor that are not currently in use. There is no need to disable an ARM processor; just don't give it instructions to execute.

When there is some work to do, the most power efficient way to do the work is to use all cores, but at the lowest possible clock rate. Power increases with the square of speed, therefore two cores at half the speed use much less power than one core at full speed.
X 2. This is exactly what I was going to say.