Root [Virgin Mobile] Are both cores on

[Piznick64]

i was looking into my cores on my phone and one of them said off, live the evo was..any way to turn both on then off when screens off

 

[BigBossman]

There is a way that may work but I strongly recommend against it because it causes the phone to act odd. There's an app originally made for HTC phones called Kernel Tuner on the market that allows access to overclocking and the activation of the second core. I would wait until a Dev makes a ROM that has True-Dual Core. You're free to try the app but I think you should make a NAND backup before altering anything

 

[Rxpert83]

You don't want both cores on when they aren't needed.


You'd just be wasting battery

 

[Piznick64]

i only want them on when im gaming or on 3g or something

 

[JupiterOne]

This is what the governors in the kernel are for. Get a tuner app and check out the governor settings. Performance gov will give you both cores BAM, on activity. I don't recommend it. If you have a modded kernel then you may have a very WIDE variety of govs. Do a search on XDA and you will be amazed at how well this is documented.

Oh yea and what Rxpert83 said!!!

 

[Palmetto Fellow]

You don't want both cores on when they aren't needed.


You'd just be wasting battery

Totally agree. Let the phone determine when the second core is needed. It kicks in pretty fast as-is so I'd just let it be.

 

[Piznick64]

doesnt only having 1 core put more stress on the cpu and everything

 

[Palmetto Fellow]

doesnt only having 1 core put more stress on the cpu and everything

No.

You actually have both cores on...or to better phrase it...both cores can be turned on rather quickly. At any given moment, your second core is turned on and goes to like 900MHz then drops back to off. Then it may come on and jump up to 1500 MHz and then drop to 900 MHz, and then turn off again.

It's more efficient to run one core all the time and the second core only as needed than it is to run both cores on at the same time all the time. If you ever watch your CPU frequencies in real time, you'll see this in action. It's cool to watch. If you've never seen this in action, then you probably assume that a 1.5GHz core means it runs at 1.5GHz. That's not true. It can run as fast as 1.5GHz, but it doesn't run that fast all the time. It only uses what it needs. It can go as low as 384MHz and as high as 1512 MHz and many spots in between.

So if your screen was on, and you were doing nothing except look at your wallpaper, your core should be somewhere between 384 and 1000 MHz...bouncing back and forth between those numbers. You'd even see an occassional jump to 1500. If you had both cores on, they would both stay between 384 and 1000 most of the time, but you'd probably still see one of them bounce up to 1500 at some point before coming back down.

In the end, there's no real reason to have a core on if there aren't enough computations taking place to need that core to be on. Keeping both cores on full time is probably more likely to contribute to extra wear and tear...at least for the second core and by creating more heat overall.

 

[Piznick64]

No.

You actually have both cores on...or to better phrase it...both cores can be turned on rather quickly. At any given moment, your second core is turned on and goes to like 900MHz then drops back to off. Then it may come on and jump up to 1500 MHz and then drop to 900 MHz, and then turn off again.

It's more efficient to run one core all the time and the second core only as needed than it is to run both cores on at the same time all the time. If you ever watch your CPU frequencies in real time, you'll see this in action. It's cool to watch. If you've never seen this in action, then you probably assume that a 1.5GHz core means it runs at 1.5GHz. That's not true. It can run as fast as 1.5GHz, but it doesn't run that fast all the time. It only uses what it needs. It can go as low as 384MHz and as high as 1512 MHz and many spots in between.

So if your screen was on, and you were doing nothing except look at your wallpaper, your core should be somewhere between 384 and 1000 MHz...bouncing back and forth between those numbers. You'd even see an occassional jump to 1500. If you had both cores on, they would both stay between 384 and 1000 most of the time, but you'd probably still see one of them bounce up to 1500 at some point before coming back down.

In the end, there's no real reason to have a core on if there aren't enough computations taking place to need that core to be on. Keeping both cores on full time is probably more likely to contribute to extra wear and tear...at least for the second core and by creating more heat overall.

oh ok i guess its different with the evo then or at least they explained it differently

 

[Palmetto Fellow]

oh ok i guess its different with the evo then or at least they explained it differently

I'm not sure how it was explained to you. I think even desktop PCs with multiple cores may use them as needed rather than having then on all the time.

I would agree that there is a theoretical increase in performance by having both cores on all the time. There are some criteria that need to be met before the second core activates. The kernel analyzes the cpu load, and if the threshold is reached, the second core activates. There are delays built in, and that increased load must be present for a period of time as well. In most cases, the second core can kick in within a half second if needed, so you aren't going to really notice any lag waiting for it to activate.

This is why I said it was a theoretical increase. There could be a situation where that half second is just too long, but I don't think I had a situation like that yet.

IMHO, the negatives far outweigh the positives for having both cores on all the time.

 

[richking34]

Yes its the same with computers, there is no way in hell that 4 cores will run a maximum all the time it would overheat and melt through the housing. The computer only uses as much as it needs for a few brief seconds and then returns to normal.

 

[maaneeack]

From what I remember when dual-cpuing linux/bsd, SMP is how they're accessed. And the kernel already has it enabled. At least I think it does based on the kernel version under settings (SMP PREEMPT).

One thing to consider is if we can set affinities. I want to play <game>, lets make the 2nd core dedicated to that and everything else continues on the first core.