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

Any recommended kernel?

I've searched but everything seems either old or non-existent. What are some of the kernels you all are using and how do you like them? Any you preferred over another? Any you recommend?
I'm currently using Salvagezen .2 CFS noSBC and it seems pretty good as far as battery life. I have previously used Tiamat, but I'm not really sure of the differences between these 2 other than obviously the developer.
FYI I'm using CM7 nightly
heres a link to my current kernel http://mirror.munkibizness.com/?nosbc

i find savagedzen's kernels are the very best there are, and i'd keep using them. if you are having problems, just say so and the team will get you sorted out in no time (yes, they are that good)

I have had a lot of luck with Netarchy's 4.3.2 series. Depending on your hardware, you will have different luck also. They seem to be real stable and have gotten me 17+ hrs. I use the heck out of my phone though.

I've also been using Netarchys kernel, but SBC. Definite improvement, never had a battery overheat.

I might try netarchy. I'm pretty sure I want noSBC just to be on the safe side. As far as the undervolting, havs, etc, I'm not sure what I want. The latest CM7 nightly stock kernel has been giving me greatly battery life lately though, so I might not even need to change.

zamboniman87 said:
I've searched but everything seems either old or non-existent. What are some of the kernels you all are using and how do you like them? Any you preferred over another? Any you recommend?
I'm currently using Salvagezen .2 CFS noSBC and it seems pretty good as far as battery life. I have previously used Tiamat, but I'm not really sure of the differences between these 2 other than obviously the developer.
FYI I'm using CM7 nightly
heres a link to my current kernel http://mirror.munkibizness.com/?nosbc
Click to expand...
Click to collapse
If you haven't done so, try the one in the signature...
Netarchy toastmod 4.3.2-cfs -nohavs-noSBC-noUV
Posting & replying via the XDA Premium app

zamboniman87 said:
I might try netarchy. I'm pretty sure I want noSBC just to be on the safe side. As far as the undervolting, havs, etc, I'm not sure what I want. The latest CM7 nightly stock kernel has been giving me greatly battery life lately though, so I might not even need to change.
Click to expand...
Click to collapse
Just make sure that you don't try Netarchy's kernels while you're still on CM7. Net's kernels are for Sense roms only, and you flash a sense kernel to an AOSP rom, you're definitely not going to have a solid experience. Stick with aosp kernels while on aosp roms.

k2buckley said:
Just make sure that you don't try Netarchy's kernels while you're still on CM7. Net's kernels are for Sense roms only, and you flash a sense kernel to an AOSP rom, you're definitely not going to have a solid experience. Stick with aosp kernels while on aosp roms.
Click to expand...
Click to collapse
oh good point! thanks.

[Q] kernals

currently running koni elite 3 and love it...was just wondering is there a kernal out there that makes this rom even faster? dont get me wrong this is way fast just wondering if it can go faster
thanks

justintammy said:
currently running koni elite 3 and love it...was just wondering is there a kernal out there that makes this rom even faster? dont get me wrong this is way fast just wondering if it can go faster
thanks
Click to expand...
Click to collapse
Netarchy's & Ziggy's kernels. Take your pick, for faster, id say bfs

blakeboys said:
Take your pick, for faster, id say bfs
Click to expand...
Click to collapse
Just to expand a little on this.
Every kernel will work differently on every EVO, small variables in the manufacturing produce a wide array of possible configurations. Try a few and decide for yourself.
Net's kernels tend to favor stability over speed.
Ziggy's tend to favor speed over stability.
CFS favors the performance of the EVO as a whole (multitasking) and will have consistent, smooth performance across the board.
BFS favors performance of the apps in the foreground, so game performance will be better, but multitasking might be laggy at times.
Good luck!

...yes try the newer NET kernels (beta) its said to be even faster! and check out the kernel guide in there. http://forum.xda-developers.com/showthread.php?t=719763

Thank you guys
Sent from my PC36100 using XDA App

mexlos said:
Just to expand a little on this.
Every kernel will work differently on every EVO, small variables in the manufacturing produce a wide array of possible configurations. Try a few and decide for yourself.
Net's kernels tend to favor stability over speed.
Ziggy's tend to favor speed over stability.
CFS favors the performance of the EVO as a whole (multitasking) and will have consistent, smooth performance across the board.
BFS favors performance of the apps in the foreground, so game performance will be better, but multitasking might be laggy at times.
Good luck!
Click to expand...
Click to collapse
Finally a good explanation

one more thing guys, what does sbc mean? again thanks for the help

umm nevermind

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?