# Kernel Break-in: Fact or Fiction?



## AshG (Jun 7, 2011)

I want to make sure I have my ducks in a row before providing new users any advice regarding this subject.

I've seen several people across several different forums talking about needing to take a few days before judging how well a kernel works in regards to performance and battery life. In the case of SOD issues or random reboots, moving to a different kernel is warranted but passing judgment on battery life and overall device performance requires a few days to accurately assess.

I'll admit to buying in to this belief; things do seem to be a little more active following a kernel install vs regularly rebooting the phone (I watch the power draw via battery monitor pro; not necessarily scientific, but it at least shows a trend) and things do seem to settle in and battery life seems more consistent after two or three days. It could be the placebo effect for all I know.

We've had the triple-wipe myth debunked. We've had the delete battery stats myth debunked. Here's hoping the brains here can help put this to rest.

Kernels need time to settle in. Fact or fiction?


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## poontab (Jun 7, 2011)

Fiction. Software is not like a beer keg. Caches need to be rebuilt but that is all.


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## AshG (Jun 7, 2011)

Sweet.


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## kevcube (Jul 25, 2011)

Ehh, the battery stats was only debunked for the Galaxy Nexus which has a special sensor to measure the charge of the battery. For almost all other phones, battery recalibration is very beneficial when flashing a new kernel.


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## carhauler1969 (Jul 28, 2011)

Fact! Here's proof in my case at least. On my EVO, Transformer, E4GT, Nook Color, & my HeroC battery life & overall system performance is always better after 48 hours. Prime example is the Tiamat 3.3.7-sbc+ kernel for the EVO, this is hands down the best performing, most stable, & most widely used & recommended kernel for the EVO 4G. *But* it is total junk for the first 36+ hours. After that even with extreme underclocking, & undervolting there is not another AOSP kernel for the EVO that can touch it, period.
I've found that the so-called break in period for kernels applies to all of my devices, every time I flash something different. Unless you're having major issues after flashing a new kernel, stick with it for at least 72 hours to really get a feel for what it's capable of both performance wise & stability wise. If all you're after is high benchmark scores, & don't care about stability, battery life, or real world day to day use of your device, then feed the flash-a-holic in you & flash to your hearts content. 

Sent from my SPH-D710 using Tapatalk


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## carhauler1969 (Jul 28, 2011)

kevcube said:


> Ehh, the battery stats was only debunked for the Galaxy Nexus which has a special sensor to measure the charge of the battery. For almost all other phones, battery recalibration is very beneficial when flashing a new kernel.


Battery stats wiping for all Android devices was, & has been debunked for quite a while. It is a totally useless procedure that has absolutely has no effect on battery life whatsoever. All you're doing is wiping the data displayed in the battery usage display in the settings menu. Nothing more, nothing less.

Sent from my SPH-D710 using Tapatalk


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## carhauler1969 (Jul 28, 2011)

AshG said:


> We've had the triple-wipe myth debunked. We've had the delete battery stats myth debunked. Here's hoping the brains here can help put this to rest.


+1
Sent from my SPH-D710 using Tapatalk


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## exarkun (Dec 4, 2011)

I have yet to see anyone provide a real answer to this other than their anecdotal evidence. A kernel does not need to "break-in" on any linux flavor I have ever installed. Only in the Android world have I heard of this. Likely due to people unfamiliar with how operating systems work.


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## Lothinator (Jun 30, 2011)

There is no reason for a break-in period. Maybe one reboot to allow caches to fully rebuild, but beyond that nope nada.

If a Kernel is giving issues by the 2nd boot, then chances are it will give issues later as well. Anecdotal observations of "well, it didn't randomly reboot after the 5th startup, so all must be fine" are usually followed up by later realization that things are still unstable.

One reason people tend to see worse battery life and "issues" during their first few startups after installing a new kernel/ROM is that they are busy configuring settings, testing things, restoring backups, etc. As soon as they're done with that then the usage patterns change, and therefore so does the observation of "kernel issues".


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## kendon (Jan 11, 2012)

kevcube said:


> Ehh, the battery stats was only debunked for the Galaxy Nexus which has a special sensor to measure the charge of the battery. For almost all other phones, battery recalibration is very beneficial when flashing a new kernel.


if only you had even the slightest evidence for what you are saying. the post about the battery stats from dianne hackborn doesn't say anything about it being device-specific. feel free to reread: https://plus.google.com/u/0/105051985738280261832/posts/FV3LVtdVxPT
if you don't believe it, do what dianne proposes in the comments to the statement: "You can look at the code for whatever platform you are running to see the format at that point."

the above, and you are confusing battery stats and battery calibration.


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## codesplice (Oct 21, 2011)

Lothinator said:


> One reason people tend to see worse battery life and "issues" during their first few startups after installing a new kernel/ROM is that they are busy configuring settings, testing things, restoring backups, etc. As soon as they're done with that then the usage patterns change, and therefore so does the observation of "kernel issues".


This. It's impossible to objectively measure battery drain immediately after flashing a new ROM/kernel/etc since you're busy getting things reconfigured to how you want and testing new features. Once the "new" has worn off (to the extent that you can actually let your phone sleep for a bit) you'll start seeing more accurate readings.


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