[Google Pixel 2 Guides, News, & Discussion] Lagarde:
Since I've seen a lot of people (somewhat unfairly) discussing one kernel in another kernel developer's threads, I thought I'd look around for a good healthy discussion of the kernels we currently have available for the Pixel 2. Not finding one, at least not recently, I figured I'd make one.

Please feel free to chime in with your experiences with the kernels, and any kernels we may have missed, as well as any fixes or tricks you've found to improve on them!

Before I get into my own anecdotal results, here's my setup for all of the following:

- Pixel 2 (duh)

- Stock ROM (haven't done anything with alternate ROMs on this phone, as most seem to be unofficial/beta yet and I use this as daily driver)

- January Pie update as of the time of this posting

- Magisk 18.0 (https://xdaforums.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445)

- Latest TWRP (https://xdaforums.com/pixel-2/development/twrp-alpha-pixel-2-t3698147)

- Basic Google apps (Chrome, Drive, Gmail, Maps, Photos, Play Music), plus Slack and Skype (work requires these), and Pandora (my sanity requires this).

- For streaming, I'm always on bluetooth and listening to Pandora. For non-streaming, I'm playing via bluetooth from local files in Play Music.

- Bluetooth is connected about 10hrs a day. Wifi is connected about 14hrs a day. Assume they're both on and likely connected during all tests.

- I use BlackenedMod for some tests and will note if I do.

- Always on display is turned on, as is OK Google.

Kernels I've tried with results:

[Flash] - https://xdaforums.com/pixel-2-xl/development/taimen-flash-kernel-1-00-t3702057

- This was my go-to. Sadly, it's discontinued. Stock experience with no frills. Rock solid. Never crashed.

- Idle, I was seeing about 2-3% drain per hour. Non-streaming music, about 10-12%. Streaming, about 15-18%.

- BlackenedMod reduced idle to about 1-2%. Non-stream to about 9%. Streaming to about 15%.

[ElementalX] - https://xdaforums.com/pixel-2/development/kernel-pixel-2-elementalx-1-00-t3719081

- Went to this kernel after Flash was discontinued. Also rock solid. Has a lot more options than stock and is updated very quickly after each monthly patch.

- Idle, about 2-3% per hour. Non-streaming, about 10-12%. Streaming, about 14-16%.

- BlackenedMod reduced idle to about 1.5%. Non-stream to about 10%. Streaming to about 15%.

- Have run into bugs where this kernel got bad wakelocks with a few apps, usually right after a monthly patch. This is usually resolved either by a Magisk or EXKM update.

[Sultan] - https://xdaforums.com/pixel-2/development/kernel-sultan-kernel-t3802158

- This is the recommended replacement for Flash. Updates are intermittent, but high quality when they do come out.

- Idle, about 1% or less per hour. Non-streaming, about 8%. Streaming, about 12-16%.

- BlackenedMod barely reduced idle to consistently 1% or less. Non-stream to about 5-6%. Streaming to about 10-13%.

- Sultan doesn't do wakelock blocking, but may not need it. Also, ran into some weird bugs with Google Assistant requiring me to cancel a request and redo it. Some Assistant requests just hang (screen shows, "Calling XYZ" but it never does anything). "OK Google" not working consistently. Sound feels a bit more flat in this kernel than the others, but I could be entirely imagining it.

[Kiri] - https://xdaforums.com/pixel-2/development/21-11-2017-kiriskura-kernel-1-0-1-t3708383

- This one's been my most frequent daily driver. Early on, I'd had reboot issues, but this appears to have been resolved over the last few updates.

- Idle, about 1% per hour. Non-streaming, about 8%. Streaming, about 13-15%.

- BlackenedMod reduced idle to <1%. Non-stream to about 6-7%. Streaming to about 12-14%.

- No bugs I've found so far. YMMV

ADDED 31-1-2019

[Evira] - https://xdaforums.com/pixel-2-xl/development/02-01-2018-evirakernel-t3885475

- Installed this right after posting after some recommendations. Feels very similar to Kiri, but with a bunch more governors.

- Idle, about 1% per hour. Non-streaming music, about 6%. Streaming, about 15-16%.

- BlackenedMod reduced idle to <1%. Non-stream to about 5-6%. Streaming to about 12-14%.

- Having intermittent issues with Skype messages not delivering, or if they do, there's no notification. Excluded Skype from battery optimization, but no change. Also, occasionally have Pandora force-close even with the screen on and phone plugged in, which is really weird.

- New bug: Battery drain is usually amazingly good at idle. 0.5%/hr is not uncommon. However, I'm seeing occasional issues where I'll have the phone idle and drain 0.5% for a couple hours, then abruptly, 10% gets drained for no reason, and then back to 0.5%/hr. Haven't been able to figure out why this happens yet.

ADDED 2/4/19

[Caesium] - https://xdaforums.com/pixel-2/development/taimen-walleye-caesium-kernel-v0-2-t3878737

- A few people recommended this one once it hit v1.0. Tested on 1.0 and now 1.1.

- True idle, about 1% per hour. Non-streaming music, about 7%. Streaming, about 12-13%. Those are the best overall numbers from any kernel I've gotten so far. More importantly, they're stable and don't wildly bounce around.

- BlackenedMod reduced true idle to <1% (around 0.5%!). Non-stream to about 6%. Streaming to about 12%.

- So far, this one's had lower drain on Bluetooth than the others, especially with idle connection. Very little random drain. Whereas Evira had spikes of drain (1%/hr overnight most of the time, then 10-15% in one hour), this has been steady. Only issue I've found is it's a bit warm with this kernel, though that doesn't seem to be causing any drain, which is rather odd. This may still be part of it settling in.

- Well, so much for the above. After doing the Feb update, now I'm burning 6%/hr at true idle, and 14%/hr with non-streaming music. Phone is HOT. Reloaded clean with Feb image and got the same results. Ouch.

Added 2/19/19

[Elixir] - Possibly DOA project!

- This one came very strongly recommended by a lot of people. Stock experience, they say. Lower battery usage, they say. YMMV. Tested 3.6 Clang version.

- True idle, I'm getting 6% per hour...yes, 6. Non-streaming music is 25%. Streaming, also 25%. These are the worst numbers I've gotten on any kernel, including stock. I've got to believe there's something messed up here, but the numbers are consistent even on a fresh install.

- BlackenedMod did not reduce drain at all on this kernel.

- Ouch. So much drain. My phone's hot enough to keep my hands warm in the freezing temps around here. I have asked in the Elixir forum thread to see if maybe they know why mine's draining so badly. Will update if something changes.

- Also worth noting, there's been NO replies on their forum thread (which is why I didn't bother linking it). I'd call this unsupported and possibly dead. Recommend not using!

One thing to note, no matter what kernel, update, script, etc, I see huge bluetooth drain when anything is playing. Idle with BT connected is fine, but I start music and it drains fast. This didn't used to occur, but one of the Google monthly updates seems to have caused this. I know a lot of folks are looking for answers to that issue, so please don't blame your kernel dev for that particular issue.

Anyone got results they want to share and anything cool they've found?