I suspected you were talking about doze. That's unrelated to the kernel.
Here's a bit of information:
Test and optimize your app for the power-saving features in Android 6.0.
developer.android.com
From that documentation: "If a user leaves a device unplugged and stationary for a period of time, with the screen off, the device enters Doze mode."
I know there are more conditions to it, but usually tweaking things like this ends in a lot of trouble.
There's a reason why the device enters the so called deep idle/doze only after a while if completely left alone. You won't receive notifications during that time.
I know it sounds tempting to play with this to make it kick in more aggressively, but usually it does more harm than good.
I'm not screwing around with doze or making it more aggressive, because I like to get my notifications during the day.