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Root Kernels

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luigic81

Android Enthusiast
So I have tried a small handful of different kernels now and was curious about a few things.
When someone says "stable" what exactly does that mean in the kernel world? No FC? No reboots?
Are no havs kernels generally faster than havs kernels? If so, how much battery life difference is there?
I've tried cfs and bfs without noticing much of a difference.... then linpak scores were different but not sure if I noticed much while using the phone. Is pretty much everyone running setcpu?
That's all for now, i plan on trying a no havs kernel for the first time tommorrow, but wanted to get some input on what to look for
 
To me stable means no force closes or random error messages or random reboots. Means I can use all my existing apps without issue from kernel to kernel. I can't really say I've noticed much difference in battery life with havs/nohavs. But screen would have issues with tearing. This might be a good read for kernels:

Composite HTC/AOSP
 
did you get screen tearing with havs or without havs?
come to think of it now, with the Netarchy BFS 4.3 havs some of my app icons disappaeared and I got some FC's
with the same kernel but CFS instead I didnt have the same probs, and seem to get slightly better battery life with CFS as well as a higher linpack score...
 
I've noticed the same with BFS and battery life. CFS has always been better for me. As for HAVS vs non-HAVS, you're unlikely to see much of a difference in battery life unless your phone spends a lot of time sleeping. It also depends on what governor you're using. If it spends a lot of time at high frequencies, it's not going to be supplying much less voltage to the cpu than normal. That's why when you're not doing a lot or just leaving the phone to sleep, it can way under-volt. With non-HAVS, it's always the same voltage, so you might notice a little bit more battery drain over longer periods of inactivity, but that's probably it. You're also extremely unlikely to have screen tearing with non-HAVS. It's usually just a problems with HAVS, but not always. Performance-wise, it's probably negligible. You're governor choice/overclocking speeds, etc. affect this a lot more.
 
luigic81 said:
did you get screen tearing with havs or without havs?
come to think of it now, with the Netarchy BFS 4.3 havs some of my app icons disappaeared and I got some FC's
with the same kernel but CFS instead I didnt have the same probs, and seem to get slightly better battery life with CFS as well as a higher linpack score...
Click to expand...


Before Netarchy 4.3.1 I would get tearing with havs. But since that release the tearing has been addressed with the havs version.
 
ok doesnt sound like there is a reason to try NO havs then, I'll play around with the governors and maybe try kings kernel in the next few days here, just to try something different, any other good kernels to try out?
 
Try the ziggy471 kernels:

Ziggy471.com Life's too short, have fun while you can.

My experience with them is that they are very efficient, and speed things up, making things smoother, but are inconsistent in terms of battery life and stability. Don't let that last part scare you. It's not like it would drop 50% over night or reboot every 5 minutes. I just mean that at times it would get good battery life, then inexplicably drop 5% or so while sleeping over a one hour period, then go back to normal. It also rebooted on me once while performance testing at 1190 MHz, so that's not exactly abnormal. It's just that netarchy was stable under the same conditions. I last tried it a few revisions back, so it might be better now. Give it a shot and see what you think.
 
luigic81 said:
ok doesnt sound like there is a reason to try NO havs then, I'll play around with the governors and maybe try kings kernel in the next few days here, just to try something different, any other good kernels to try out?
Click to expand...

Dont disregard no havs so fast... When i was using myns Rls4 the only kernals my phone had great battery life with was Netarchy no havs...

It really depends on your phone... So on your quest for your perfect kernal you might want to give it a shot.
 
Jayo619 said:
Dont disregard no havs so fast... When i was using myns Rls4 the only kernals my phone had great battery life with was Netarchy no havs...

It really depends on your phone... So on your quest for your perfect kernal you might want to give it a shot.
Click to expand...

thanks for the input, I do get pretty decent battery life, and I havent had any issues with the havs kernels so far, but I agree with you, I should try some too just to find out.
But at the moment I'm addicted to speed over battery life, so my quest starts there :)
 
Can someone explain what havs and no havs mean? Also the difference with cfs and bfs. and i think SBC are the trickle charge kernels correct? I have myn's rls5 with its stock kernel.
 
ocnbrze said:
Can someone explain what havs and no havs mean? Also the difference with cfs and bfs. and i think SBC are the trickle charge kernels correct? I have myn's rls5 with its stock kernel.
Click to expand...

This has been covered in great detail elsewhere, so I'll give you a brief description:

HAVS - Hybrid Adaptive Voltage Scaling. What that means is that as the CPU frequency scales up and down based on load (determined by the governor), the amount of voltage supplied to the CPU will go up or down. Basically, it keeps the voltage as low as it possibly can for a given frequency, and steps it up for each frequency change. So, if you have the screen off, the CPU will be running much slower. It doesn't need as much voltage, so it drops down how much is supplied. As you start using the phone, it increases the voltage.

Non-HAVS - A constant voltage is supplied to the CPU. The CPU still scales the frequency up and down, but the voltage stays the same. This is how the stock kernel operates.

CFS/BFS:

Completely Fair Scheduler - Wikipedia, the free encyclopedia
Brain **** Scheduler - Wikipedia, the free encyclopedia

And, yes, sbc kernels are the ones that trickle charge the battery.
 
trying out ziggy's lastest CFS today, for some reason there are alot more scaling options in setcpu with this kernel
 
luigic81 said:
trying out ziggy's lastest CFS today, for some reason there are alot more scaling options in setcpu with this kernel
Click to expand...

They have to be included in the kernel by the developer. Which one to use is up to you, but as you switch kernels, you'll see the options that the developer has included.
 
so far I like ziggy's best using on demand scaling, havent messed with the "interactive" too much. we'll see how the battery lasts with "on demand"
 
luigic81 said:
so far I like ziggy's best using on demand scaling, havent messed with the "interactive" too much. we'll see how the battery lasts with "on demand"
Click to expand...

Don't expect amazing battery life with ondemand. It spends a lot of time at higher frequencies, and jumps between the min and max, with very little stepping up/down. It makes things a little more responsive, but it seriously isn't the most battery friendly option. Of course, YMMV.
 
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