Develop Bugs

[Q] what is a kernel?

I know this is a really noob question, but what is a kernel? I see them all over the developer section when i look for roms, but i have no clue what it is (sorry if this is a bumped thread).

I also wanna know cuz i would like to use the right kernel to my incredible....
Sent from my Incredible using XDA App

A kernel is the bridge between the hardware (for example processor, memory, nand) and the software (the ROM). This is why changing the kernel can have such a huge impact on battery or speed. For example, one kernel can tell the processor to work its butt off, which decreases battery, while another will tell the processor to relax, increasing the battery life but decreasing speed. Since every processor is made from different silicon, not every kernel fits all phones.
Also, in kernels another important thing is the task scheduler. The Brain **** Scheduler (BFS) basically has ups and downs in performance but the Completely Fair Schedulare (CFS) is pretty much consistent in performance. It's hard to explain. I personally prefer BFS over CFS. Also, if you want higher quadrant scores, use BFS.
Hope this helps.

Thank you so much!

AOSP or Sense - it matters to the kernel
Noteworthy when flashing a kernel -
AOSP ROMs require AOSP kernels, Sense requires Sense kernels.
Same story with Froyo or Gingerbread ROMs, either AOSP or Sense.
Bootloops happen when they get mixed.

Great explanation, thanks- I was too embarrassed to ask, so I used the search...and here it was! finally I have a clue

smtom said:
Noteworthy when flashing a kernel -
AOSP ROMs require AOSP kernels, Sense requires Sense kernels.
Same story with Froyo or Gingerbread ROMs, either AOSP or Sense.
Bootloops happen when they get mixed.
Click to expand...
Click to collapse
Except that i have used ziggys latest bfs wo havs on cm7 an z roms
Sent from my ADR6300 using XDA App

Help with FPS and scrolling laginess, TIPS?

Hello all. I wanted to see if tips could be posted on how to increase scrolling laginess and increase fps in things like video and games. I bought my wife the shift and Ive noticed its alot better at mobile gaiming and video playback/recording.
Ive rooted and installed myns warm two point two along with netarchy-toastmod 4.3.4 cfs havs more nosbc.
Ive overclocked to 1.2ghz using setcpu and left the governor on smartass. (no profiles)
These seem to have made a visual improvement, but I want/need more.
So my questionis are...
Is there specific kernels that will help get the results Im looking for? (Im more insterested in performace, but would like batterly life is possible)
Are there any hidden tips that can be done via command line etc that will change things to allow for a better fps performance?
ANy help, links, etc will be appreciated. Ive been searching for weeks already just to get myself rooted/romed/kerneled.

The Shift has a better processor and a better GPU. I don't think you're going to be able to match it by overclocking. There are ROMs that tend to be a little smoother than others (MikFroyo 4.6 is nice), but there's only so much that can be done with the hardware. The Evo itself is almost a year old, and the QSD8650 SoC it uses has been available since Q4 2008.

sinnedone said:
Hello all. I wanted to see if tips could be posted on how to increase scrolling laginess and increase fps in things like video and games. I bought my wife the shift and Ive noticed its alot better at mobile gaiming and video playback/recording.
Ive rooted and installed myns warm two point two along with netarchy-toastmod 4.3.4 cfs havs more nosbc.
Ive overclocked to 1.2ghz using setcpu and left the governor on smartass. (no profiles)
These seem to have made a visual improvement, but I want/need more.
So my questionis are...
Is there specific kernels that will help get the results Im looking for? (Im more insterested in performace, but would like batterly life is possible)
Are there any hidden tips that can be done via command line etc that will change things to allow for a better fps performance?
ANy help, links, etc will be appreciated. Ive been searching for weeks already just to get myself rooted/romed/kerneled.
Click to expand...
Click to collapse
As bkrodgers said, the Shift has better hardware than the Evo. My roomate has one, and that thing really is smooth, even on the stock rom. It nailed like 1400 or something like that on quadrant, not even overclocked on a stock rom. The only changes I ever make to my phone that affects the scrolling is the kernel. My phone doesn't like havs, the voltage scaling makes it unstable, and it lags severely, on any havs kernel. I get the smoothest experience out of my device from a kernel that has no havs and isn't undervolted. Of course, you get bettery battery life out of a kernel with havs, if your phone can tolerate it. Every phone acts differently on different kernels, which is why there are so many to choose from. So you can find the one that's 'just right' on your device. It takes a little playing around and kernel swapping to find the right combo. And as far as I know, basically all the kernels that have been available for a good number of months now, have the fps fix already baked in. When the Evo's first came out, FPS was capped at 30fps. Since then, all the custom kernels allow for it to go much higher than that, sometimes up to 60fps. I don't believe there's much more you can do with that.
Also, for what it's worth, you might want to try out an AOSP rom. They have much less crap in them, and they tend to run very very smooth (in my experiences). Not to talk down on any sense rom, as I also love sense, and 99% of the time and more than happy on whatever sense rom I happen to be running at the time. Fortunately, the Evo has quite a few selections on roms and kernels, so there is quite a bit of playing around and tweaking you can do, in search of the perfect setup.

thanks I'll probably try miks rom to see how that goes.
I understand about the hardware and that the shift has a better cpu, but is there anything else other than what I have already done to make everything nice and speedy UI wise? I think the biggest culprit is the app drawer being clunky. (like this on the shift as well) No settings in linux that can help there?
Oh and kernels. Ive tried 2 of netarchy-toastmods kernels and havent really noticed a difference. Both have had havs. Should I stay away from these type of kernels to get better visual performance?
ANy other tips on which kernels youve tried and noticed better ui results?
ah yes the elections are great. lol I guess I'll have to try a non havs kernel to see how they perform along with the senseless roms.
Thanks all

sinnedone said:
thanks I'll probably try miks rom to see how that goes.
I understand about the hardware and that the shift has a better cpu, but is there anything else other than what I have already done to make everything nice and speedy UI wise? I think the biggest culprit is the app drawer being clunky. (like this on the shift as well) No settings in linux that can help there?
Oh and kernels. Ive tried 2 of netarchy-toastmods kernels and havent really noticed a difference. Both have had havs. Should I stay away from these type of kernels to get better visual performance?
ANy other tips on which kernels youve tried and noticed better ui results?
ah yes the elections are great. lol I guess I'll have to try a non havs kernel to see how they perform along with the senseless roms.
Thanks all
Click to expand...
Click to collapse
You're welcome. Just bear in mind, that if you do try out an AOSP rom, that they have different kernels to use. You must use a kernel that was made for AOSP on an AOSP rom. So don't go trying a netarchy kernel on an AOSP rom
Also, I didn't have as good a luck with net's 4.3.4 kernel's as I did on the 4.2.2 or 4.3.2. Also the 4.1.9 kernel's worked great for me. For some reason, the newest one's don't give me the best performance.
As far as tweaking things using ADB, I don't think there's anything you can do FPS related. I believe there are ways to adjust the undervolting in a kernel, using adb, and things like that. But as far as I know, the FPS is what it is at this point, although it will vary from kernel to kernel.

Best rom/kernal combination

I'm pretty sure that this question has been posted alot of times but I need help deciding on a decent rom and a kernal which would go with it that has everything working and has the best battery life as well. I will probably get CM7 but idk which kernal will go best with it.
I also need help changing the LCD density of my screen. Before I switched to my EVO I owned a HTC HD2 and had pongsters hyperdroid on it which had lower LCD density allowing everything to be smaller on the phone.
Those are my questions please help. Thank you!
Sent from my PC36100 using xda premium

Not exactly sure what you mean by LCD density but I can help with the ROM kernel question.
As far as a ROM goes the best way to find the right one is to do 2 things.
1. Make a list of things you are looking for in a ROM. Stability, 4G, HDMI, Wireless Tether, etc. Then check out ROMs that contain stable versions with those features you emphasize.
2. Get flash happy. Flash a ROM, test it for a few days to a week and then flash another one. If you find yourself coming back to one specific ROM over and over again then that is probably the one you should stick with.
Check out this thread for some ROM ideas: http://forum.xda-developers.com/showthread.php?t=951057
A few ROMs that I didn't see mentioned in there are Myn's Synergy, Salvage-Mod, Sinister, Savaged Zen, and Swag.
As far as kernels go you have to remember a basic rule. Sense ROMs get paired with sense kernels and AOSP ROMs get paired with AOSP kernels. Then you do the same thing you did with the ROMs.
1. Make a list of what you want in a kernel. HAVS, SBC, overclocking, undervolting, etc.
2. Get flash happy and test which kernel matches your ROM the best with what you are looking for.
I know that may not be the exact answer you are looking for. But ROMs and kernels are all about personal preference and daily usage trends. each one has pros and cons that different people may or may not like. Check my ROM/kernel combination. It fits my usage habits, constantly using it at home and barely use it when out of the house, but it may not fit the way you use it. Experiment and have fun.
And here is a thread about kernels: http://forum.xda-developers.com/showthread.php?t=894880

Quite personally, I would suggest MIUI. If you're not into that kind of thing, I would suggest Deck's, who updated to stable yesterday!
Kernel, I would say Tiamat 4.0.8.
Look up Vipermod. Check my signature. Most phones can at least handle a -50 undervolt for the Tiamat mentioned above.
I would suggest the flashable GPS fix in my signature. Locks on quite accurately.
You may have a lot of cell standby drain. Check development section for a thread about Radio wakelock combination.
Best way to change the density would be to edit the build.prop but there are apps in the Market. Just search density changer
Sent from my PC36100 using xda premium

Flash Flash Flash
Then you will be able to find out what you like.
AOSP is always a winner for me.
Oh, and make sure you Nandroid.

I agree with both posts above, you have to try out roms for yourself since in every rom post you will see someone saying this is the best rom they have ever hadand battery life is super. Your question has been asked a million times before but like that millions of answers that were given it all boils down to personal choice.
I run AOSP with an sbc kernel but Lord knows you may find people here who would dispute the use of an sbc kernel. LCD Density apps are in the market or just use google for help. Sorry this is not a definitive answer but honestly just find a rom you like and give it a shot....

Thanks for all your answers time to get flash happy!
Sent from my PC36100 using xda premium

For me the best combo of performance and battery life has been SavagedZen and CM7. Completely transformed my perception of just well the evo should perform. Basically no compromises, Fast AND great battery life.

I'm using MikG 2.56 ROM with Aggressive Freedom kernel. Holding up pretty good.

For me the best combo is Decks Rom 1.3 + SavagedZen Kernel + Vipermod

I can get about 16 hours on MikG 2.56 (stock kernel) with moderate use. Damn near perfect ROM.

sai_iii said:
For me the best combo of performance and battery life has been SavagedZen and CM7. Completely transformed my perception of just well the evo should perform. Basically no compromises, Fast AND great battery life.
Click to expand...
Click to collapse
Which version of CM7 are you running? I'm on the 219 nightly and it kind of meh. I've tried savaged Zen with CM7.1 and it was good but my battery didn't seem to last as long during use so I decided to move on to other kernels. Are you running any supplementary battery apps?

[Q] GNexus Kernel Choice

Loving my GNex, however I've only had it a couple weeks.
There are several kernels out there, and from comparing all of them and reading all the threads as much as I can, they all seem to have relatively similar features... I'm having a hard time picking one.
Is there someone who can clarify the differentiating features of each kernel? Are certain kernels better suited for different ROMs? Do certain ones have compatibility or other persistent issues?
Mainly:
faux123
franco
GlaDOS
jamesbond
Trinity
I've tried faux123 015m (loved faux's kernels on the Sensation, but I had some mobile data issues with it on the GN) and Trinity (latest seems fast/stable, except the color profile was messing with me). I'm trying GlaDOS now. Again, though, I'm not sure what advantages or perks one kernel flavor gives me over the next. Can anyone shed some light?

grivad said:
Loving my GNex, however I've only had it a couple weeks.
There are several kernels out there, and from comparing all of them and reading all the threads as much as I can, they all seem to have relatively similar features... I'm having a hard time picking one.
Is there someone who can clarify the differentiating features of each kernel? Are certain kernels better suited for different ROMs? Do certain ones have compatibility or other persistent issues?
Mainly:
faux123
franco
GlaDOS
jamesbond
Trinity
I've tried faux123 015m (loved faux's kernels on the Sensation, but I had some mobile data issues with it on the GN) and Trinity (latest seems fast/stable, except the color profile was messing with me). I'm trying GlaDOS now. Again, though, I'm not sure what advantages or perks one kernel flavor gives me over the next. Can anyone shed some light?
Click to expand...
Click to collapse
I have tried them all myself at one time or another and i always come back to GLaDOS. I chose to run this because of the unique and innovative features Ezekeel has developed plus the great battery life. BLX, Vibration control, Touch Wake and of course the Wheatley Governor which was developed for this kernel to give the best performance and battery life, which in fact it does. The GLaDOS control app is great too and Ezekeel is always updating and making it better.
GLaDOS is exclusive to Rootzwiki that why you don't see too much mention of it here unfortunately ... I'm not even sure if Ezekeel lurks around here anymore?

Leankernel for me

blowtorch said:
I have tried them all myself at one time or another and i always come back to GLaDOS. I chose to run this because of the unique and innovative features Ezekeel has developed plus the great battery life. BLX, Vibration control, Touch Wake and of course the Wheatley Governor which was developed for this kernel to give the best performance and battery life, which in fact it does. The GLaDOS control app is great too and Ezekeel is always updating and making it better.
GLaDOS is exclusive to Rootzwiki that why you don't see too much mention of it here unfortunately ... I'm not even sure if Ezekeel lurks around here anymore?
Click to expand...
Click to collapse
I noticed he released a control app, I may give it a try!

franco

Thanks for your responses!
However it looks like people are just posting what they use. What I'm looking for is information on what differentiates each kernel.. what is each kernel's "claim to fame"? From what I've seen, all of the kernels' features look pretty similar.
For example, "X kernel balance performance and battery really well. Y kernel reduces the voltage to the screen to further battery savings. Z kernel is more focused on performance. A kernel allows your phone to make popcorn." etc.
Or are they basically the same?
Thanks blowtorch for giving some information as to what differentiates GlaDOS from the rest

grivad said:
Thanks for your responses!
However it looks like people are just posting what they use. What I'm looking for is information on what differentiates each kernel.. what is each kernel's "claim to fame"? From what I've seen, all of the kernels' features look pretty similar.
For example, "X kernel balance performance and battery really well. Y kernel reduces the voltage to the screen to further battery savings. Z kernel is more focused on performance. A kernel allows your phone to make popcorn." etc.
Or are they basically the same?
Thanks blowtorch for giving some information as to what differentiates GlaDOS from the rest
Click to expand...
Click to collapse
Jamesbond will likely give you best battery life and stability. He has a couple of other kernels with some performance boost. Glados was buggy as hell and some other things but that is for you to decide. Other kernels for me were kind of meh. I honestly dont understand how so many people say this kernel or that kernel is the best or best on battery life when so many tweaks in X kernel add more performance at the cost of mah. I liked glados and its features a lot but it came at a cost too high. Touchwake is a really nice feature in it and i am surprised more people don't ask for it. Another kernel i liked was bamf paradigm but i am not using it. I would like to try that rom again in the future but it wasnt ready for me personally. Havent tried franco's at all. Just seems to be feature packed kernel but for what?
Sent from my GT-P3113 using XDA Premium HD app

I like francos so far works great with my favorite rom AOKP, buttery smooth, stable as hell, you can go battery saver or performance since you can OC/UV, etc, if you buy the App in play store it works great cuz he updates the kernel oftem and you can use either milestone versions or nihgtlies, and has the option for autodownload and autoflash the lastests updates.
You can change screen color values, as i said oc/uv, change the boot animation, and plenty other stuff..
Thats my 2 cents on your research
Edit: forgot to tell you, he also has a support mail , and if you have any issue kernel related he will answer with a solution if possible.. Report bugs etc
Sent from my Galaxy Nexus using xda premium

Sorry miss clicked and double posted
Sent from my Galaxy Nexus using xda premium

@rbiter said:
Jamesbond will likely give you best battery life and stability. He has a couple of other kernels with some performance boost. Glados was buggy as hell and some other things but that is for you to decide. Other kernels for me were kind of meh. I honestly dont understand how so many people say this kernel or that kernel is the best or best on battery life when so many tweaks in X kernel add more performance at the cost of mah. I liked glados and its features a lot but it came at a cost too high. Touchwake is a really nice feature in it and i am surprised more people don't ask for it. Another kernel i liked was bamf paradigm but i am not using it. I would like to try that rom again in the future but it wasnt ready for me personally. Havent tried franco's at all. Just seems to be feature packed kernel but for what?
Sent from my GT-P3113 using XDA Premium HD app
Click to expand...
Click to collapse
GLaDOS has been bug free for at least the last 5 revisions

blowtorch said:
GLaDOS has been bug free for at least the last 5 revisions
Click to expand...
Click to collapse
Really? Then where is all that code he thought unnecessary but needs to go back add in?
Sent from my GT-P3113 using xda premium

And the speaker crackling randomly or playing when it feels like it? Or the extremely slow refill ratemoccasiinally?
Sent from my GT-P3113 using xda premium

@rbiter said:
Really? Then where is all that code he thought unnecessary but needs to go back add in?
Sent from my GT-P3113 using xda premium
Click to expand...
Click to collapse
I really don't know what you are talking about there unless its the bluetooth drivers that were re-added a few builds ago?
@rbiter said:
And the speaker crackling randomly or playing when it feels like it? Or the extremely slow refill ratemoccasiinally?
Sent from my GT-P3113 using xda premium
Click to expand...
Click to collapse
never seen any of these problems ...

@rbiter said:
And the speaker crackling randomly or playing when it feels like it? Or the extremely slow refill ratemoccasiinally?
Sent from my GT-P3113 using xda premium
Click to expand...
Click to collapse
I've been using GlaDOS for the last couple days and haven't had any of these issues. Bluetooth is working perfectly, even over my car's hands-free setup which has been problematic with some kernels, and audio is working perfectly... maybe you were on an older build?
Anyone have any other info? I'm surprised nobody has said anything about faux or Trinity..

Well I guess I'll be the first to represent faux kernel over here. Like that its not over done and no special app is needed to control it and the gamma control from panda board he forward ported is pretty slick if you ask me
Sent from my Galaxy Nexus using xda premium

grivad said:
I've been using GlaDOS for the last couple days and haven't had any of these issues. Bluetooth is working perfectly, even over my car's hands-free setup which has been problematic with some kernels, and audio is working perfectly... maybe you were on an older build?
Anyone have any other info? I'm surprised nobody has said anything about faux or Trinity..
Click to expand...
Click to collapse
Trinity is legendary ... never got around to faux
I'm sticking with CM9 Kernel for now it's as good as the rest IMO plus they are integrating more and more into it ... missing touch wake though from GLaDOS, oh well
I'm mainly looking for battery life now. I don't really notice much difference between most of these kernels in terms of battery life. All of these kernels have good performance without overclocking.
I find that i bounce around from kernel to kernel and in the end when all is said and done no kernel is better than the other and it really comes down to preference.

Which kernel do you prefer for best battery backup?

I am not asking which one is the best, but which one would you prefer for best battery backup? Samsung's latest release is forcing me to use a custom kernel, but I'd like to know which one I should use as I am not freak about flashing plenty stuffs.
Thanks in advance.

Redpill or uneak or perseus. You can try them all.
Sent from my GT-N7100 using xda app-developers app

Yeah, but I don't want to try them all bro. I know they all are great but that's why I asked which one is the preferable for battery backup specifically.
I am on Perseus now, I hope I've made the right choice. Lets see...

Persues is good for battery.neak is battery drainer.my experience

You're not asking which ones the best, but I'll tell you. I have used all the available kernels for my Note 2, and in my experience RedPill is the only one that is giving me consistent and best battery and overall performance. With more and more updates the developer has been adding more and more options. You can also undervolt the CPU and GPU with RedPill for further enhance your battery life. I had huge battery problems on my S3, So i had to go through a bunch of crap like different custom roms, undervolting, under-clocking etc to achieve good battery life. But when i got my Note 2 i used it for a few days completely stock and un-modified. And i was surprised at how amazing the battery life was. But if your having problems i can recommend AllianceRom + RedPill kernel, than undervolt the CPU/GPU (The utility needed to do so comes with the kernel, after flashing there will be an app installed on the phone called STweaks). And do some other minor adjustments to achieve incredible battery life. If you need any help or additional information you can contact me anytime.

I also want to know...
I would also like to know this as well. Since upgrading to 4.1.2 I am having bad battery backup, never thought of switching kernels but now I have to.
Shame on you Samsung....