ChromiumRP V0.4 - Release Notes

Release Notes - V0.4 - ChromiumRPI - https://www.reddit.com/r/ChromiumRPI/

This release contains improvements in various different areas:

Performance:
- we have switched to the Ondemand governor which puts an end to the previous situation in which we constantly locked the CPU to a fixed clock speed. Since the CPU frequency will NOT permanently be set to the lowest or highest frequency, we are able to safely profit from the benefits of a slight overclocking from previously 900MHz to now 1GHz on all cores. This is an effective 10% performance boost in theoretical computing power and the benefits of this can be observed during CPU intensive tasks. Expect an overall speedup.
- since the RaspberryPi2 only contains four cores with a single thread on each core and the CPUs do not achieve the performance of other current ChromeOS/Chromium OS devices, we have decided to switch from the standard Linux CFS kernel scheduler to the -gc scheduler branch which is maintained by Albert Chen ( http://cchalpha.blogspot.com ) and which is a modification of the BFS scheduler. This scheduler is optimized for desktop systems, focusing on extremely low latency for UI and related tasks.
- boot performance: switched to the LZ4 for kernel compression, which is the fastest available kernel compression algorithm, in order to increase the speed of the boot process
- several other kernel related tweaks, mainly focused on improving latency, interactivity and some first attempts of trimming down the kernel size (currently we are still building modules for a variety of hardware that the RasPi supports, but for which there is no real use-case under Chromium OS; some of this has been removed and the process is ongoing)

Storage:
- we have switched over from the standard CFQ i/o-scheduler to BFQ which results in slight storage read/write access latency improvements. Since we are using flash storage, those improvements will not be as extreme as if we were using HDDs, but this should still improve latency under several conditions (BFQ will replace CFQ in upcoming Linux kernels anyway)
- mounting all partitions without atime: Since our OS operates on slow microSD-card flash storage, we need to ensure that there are as few i/o-related bottlenecks as possible. Due to this we decided to turn off the atime file access time-stamps which results in less i/o operations on the sdcard
- the system will perform a trim operation on the stateful partition on roughly every fifth boot in order to avoid speed degradation of the flash storage. While not being as effective as on e.g. SSDs, using trim on simple sd-cards will still result in speedier write operations after trim has been executed
- increased the available free storage on the stateful partition: previously, only around 200MB of free storage space was available per user. This has been increased to 2GB   which should be sufficient for most people

UX:
- Google APIs are built-in, so no manual steps are required before being able to log into your Google account
- automatic time synchronization on boot: No manual steps are required in order to set the time, as it will now been synced automatically as soon as the system boots. Since the time is being synchronized over the network, internet connectivity must be guaranteed during boot
- zram is activated per default: As on all proper ChromeOS devices, the system now uses zram. The compression ratio is roughly 3:1 so a user will be able to open three times as many tabs as on V0.3 before the LMK is being triggered. The compression algorithm is LZ4 which ensures that the impact on the CPU will be as slight as possible when reading/writing to zram
- improved stability: R49 is now stable, whereas the R49 release that V0.3 was based on was still in development. Therefore, this build is officially based on stable sources


Known issues:
- Netflix doesn't work (don't ask)
- WIFI: This build is for systems using Ethernet, as the RasPi doesn't contain a Wi-Fi module and those are an optional accessory. Kindly refer to our separate guide in order to enable Wi-Fi, which might or might not work with your adapter: http://pastebin.com/F5jKLKC6
- Low-Fi TVs and TVs with resolutions lower than Full-HD might not work with this. This is being developed on 1080p screens which will also show a verified resolution of 1920x1080. TVs with lower resolutions often don't work at all, sorry about that
- Regarding the above: We do not use any boot splash screens: if you get a black screen for more than one minute, you are most likely using an incompatible TV. The boot process only takes a couple of seconds, so there is no need waiting for longer than roughly a minute for it to boot
- YouTube 4K HFR videos don't run perfectly without stutters: The RaspberryPi2 might be the wrong device for this (HD videos in full screen are now running smoothly for the most part, while still showing the occasional stutter)
- If you don't ensure you can connect to the Internet, then you won't have the date/time set automatically: This is not a bug, this is just a reminder in order to guarantee that you are connected via Ethernet when turning the device on, in case you do not want to set the time manually
- The image doesn't use all the space you have available on your microSD card: We have already increased the available size to 2GB of free space that is available to the user. Since we cannot afford to offer 16 or 32GB images for download and automatic resizing is technically not possible at this stage, you have the option to manually resize the relevant partition via modifying the image on a Linux-based system if you need more space than 2GB
- Automatic screen rotation doesn't work