[Google Pixel XL Guides, News, & Discussion] fizbanrapper:
I meant the "give it a week or more" as more of a tongue in cheek comment. Truth be told, we should expect that this might take months until we get better optimized builds etc. Folks get one OTA for Oreo and have a few problems and are ready to declare it a failed android version entirely.

I think some folks don't really understand exactly how many under the hood changes were made on the Pixel for Oreo, especially surrounding the HAL and Treble. They also don't understand the benefits of those changes and what a huge "first" this is. The entire HAL prior to O, was an archaic nightmare of binaries that existed in kernelspace. The OS ran on the assumption that the HAL had what was needed in order to execute a desired function and that's all there was to it. If the binaries weren't up to date, things would fail and it was up to the OEM to catch it and troubleshoot the failure with limited assistance from the hardware vendors. Though the OEMs try, garbage still makes it through. This is one of the reasons why pretty much all of us have had a device with stock software that eventually freezes up and won't complete a boot cycle or the camera mysteriously stops working, but works just fine after re-flashing the factory OEM image (which likely doesn't cure the root problem permanently, better luck if you have a google device). With Oreo, the software gains the ability to query the HAL to determine what its capabilities are and how it needs to interact with it. This required a TON of re-engineering by rewriting large parts of the HAL for a given device and elevates quite a bit into userspace. Nobody has done this before, but this is step 1 to addressing fragmentation. Oreo also has the capability of falling back into legacy mode which is how Angler works full time on O; it's not ever going to be Treble compliant.

This is the first version of android where this functionality has existed. It's likely that there is additional overhead incurred by having a more interactive HAL built to be Treble compliant, and that this is one of the (perhaps many) causes of the drain. I expect future OTAs will address that problem, but that remains to be seen. In the meantime... you can be delighted in knowing that after Google stops upgrading Pixel to new android versions, third party ROMs should be able to continue providing proper support to the device much easier and for much longer than they could for the Nexus line. Our phones are lasting longer than ever now, and I look forward to having my Pixel running at top speeds on android Z ;)

---------- Post added at 06:51 PM ---------- Previous post was at 06:43 PM ----------

As for fragmentation, I'm expecting that Google will implement step 2 in android "P" and this will involve a formal API which will make it easier for OEMs to customize android. I doubt this makes it into Pixel 2 and Oreo, but I expect Pixel 3 and "P" will see the creation of a separate partition for OEM mods. Google will push system images to every device running android (P & higher), even if the OEM partition hasn't been updated just yet. A query similar to Treble (but not really) will exist between OEM and system partition to resolve differences in versions and what mode the OS needs to run in.

Why do I think this will happen and what evidence do I have? Nothing conclusive, but it seems obvious if you examine the facts. The biggest threat to Android’s existence at present, is fragmentation. Only the flagships get updated. Even then it usually sucks. Security continues to get more and more attention every year. Unless something changes in a huge way, fragmentation will eventually ruin Android through security loopholes and exploits that hit the news. Given that there are over 100 OEMs that make Android phones, Google can’t trust them to update things on their own.

Also consider that, in order for a device to be certified as Treble compliant, the OEM must demonstrate that their device can run a vanilla factory image that google provides to the OEM without any OEM mods. I think that’s very interesting and provides a lot of insight into the future direction of android.