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Development [r2] arter97 kernel for OnePlus 9 series

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arter97

Recognized Developer
Oct 14, 2012
3,781
33,941
23
Seoul
arter97-xda.png



arter97 kernel for OnePlus 9 series running OxygenOS

/* Features */

Supports OnePlus 9 series
Fully rebased kernel without unnecessary OnePlus code
Latest CAF msm-5.4 kernel fully merged
Latest Linux v5.4 subversion merged
Latest Google’s security fix merged
BBR as the default TCP network congestion control
Features the latest WireGuard
Modules support disabled for lighter kernel
Latest Wi-Fi drivers from Qualcomm with customized config
Built with Clang 12 and ThinLTO
Power optimizations
Memory management optimizations
Latest SELinux subsystem backported from mainline
Latest f2fs backported from mainline
Latest BFQ I/O scheduler backported from mainline
mmap/mremap backported from mainline for a major performance boost
Touchscreen optimizations for lower latency
Uses LRNG for better performance

/* Details */

- Fully rebased kernel without unnecessary OnePlus code -



This kernel is not based on the stock OxygenOS kernel source provided by OnePlus. Instead, it’s based on the latest and greatest Qualcomm has to offer. Only the necessary parts from the OnePlus kernel have been cherry-picked, such as OnePlus 9 specific device drivers.

This effectively kills all kernel modifications/optimizations from OnePlus, including the infamous app throttler.
Due to the completely different base, this kernel will behave drastically different from other kernels, in both good and bad ways.


- Power optimizations -


This kernel makes some conscious decisions for reducing power consumption.

First, the stock OnePlus configuration forces display-related processes to use the big cores exclusively.
This configuration brings a huge power regression since it makes every frame dispatch to wake up and use the power-hungry cores.

This kernel resets this profile to use the configuration Google recommends, which is to use the LITTLE cores exclusively instead. (Reverted in r2 as it seems like that little cores aren't enough to drive 120 Hz fluidly.)
This kernel allows these processes to use little and middle cores (0-6), depending on the load.

Second, this kernel disables wakelocks upon Wi-Fi’s RX unicast packet transmissions. qcom_rx_wakelock is one of the major culprits to increased idle power consumption. Although its total wakelock time is quite low, it's catched very frequently and prevents the system from entering suspend repeatedly.

As dropping unicast or local ARP packets doesn’t pose practical issues on Android, this kernel disables qcom_rx_wakelock.

Third, this kernel reduces the duration of the Bluetooth ISR wakelock from 2 seconds to 100ms. This was done from an observation that the average userspace response time from ISR is less than 10ms.
My kernels have been doing this for years and no Bluetooth-related issues were reported.

Fourth, the vibrator driver used in this kernel no longer controls the cpuidle driver. The stock kernel disables the cpuidle whenever the vibrator is used. This kernel disables it as the vibrator is not that sensitive to deadline misses.

There are other small improvements throughout the kernel tree as well.


- Memory management optimizations -


This kernel disables LMKD and uses an in-kernel solution called SimpleLMK, made by kerneltoast. You can track how often SimpleLMK kicks in by monitoring:
Code:
/sys/module/lowmemorykiller/parameters/lmk_count

This kernel also changes a lot related to swap and zram.

The swap-related code has been backported from Linux v5.9 (link1, link2) to efficiently support fast swap device and allow swappiness over 100. This kernel currently sets swappiness to 160 on < 6GB of RAM, 120 on 8GB and 90 on 12GB.

zram has been also backported from mainline Linux and further tweaked to use block device writeback. This is equivalent to the recent “RAM Plus” feature that companies have been marketing that uses the internal storage to extend RAM.

This kernel uses zram writeback to offload idle pages (i.e., really, really unused RAM) to the internal storage. As it's extremely slow to bring pages back from UFS, writeback code works quite conservatively. It'll start to writeback pages that haven't been used for a day or two. It makes use of the hidden 2GB “last_parti” partition from the UFS storage.

Along with zram writeback, this kernel also enables deduplication with xxHash. Each page stored in zram is checked for deduplication to further save memory. With these 2 features combined, RAM reaching 1GB is additionally saved, but your mileage may vary.

The post boot script used in the stock ROM is also overridden and it sets the readahead to 128KB. As I/O workload under Android is mostly random, high readahead doesn’t help and only increases memory thrashing.

This kernel also incorporates a lot of patches to reduce/optimize memory allocations used throughout the entire kernel.

mmap/mremap code was also backported from Linux v5.10 to optimize ART (see here for more info).


- Latest subsystems -


This kernel backports the SELinux subsystem from mainline Linux. This includes caching improvements that drastically reduces time spent on lookups. 10K lines of code has been changed.

This kernel also backports f2fs (Flash-Friendly File System) from mainline Linux. This includes bug fixes and performance improvements such as shorter discard latency, more optimized GC logic for Android, and checkpoint merging.

BFQ I/O scheduler has also been backported from mainline Linux for better I/O performance.


- LRNG -


This kernel ditches the traditional RNG driver from the Linux kernel in favor of LRNG. See here and here for more info.

A rudimentary throughput benchmark shows an improvement of 10.5% (keep in mind that this is only one aspect of an RNG metric).


/* Notice */

Only OxygenOS on Android 11 is supported.

This kernel touches vendor_boot and dtbo partitions, meaning you'd need to restore said partitions whenever you're switching to another kernel or stock.
Please make a back-up of these partitions. The installer doesn’t do this automatically for you. Installing the stock ROM with a full OTA restores said partitions as well.

/* Disclaimer */

Your warranty is now void.
I am not responsible for bricked devices, dead SD cards,
thermonuclear war, or you getting fired because the alarm app failed. Please
do some research if you have any concerns about features included in this kernel
before flashing it! YOU are choosing to make these modifications, and if
you point the finger at me for messing up your device, I will laugh at you. Hard. A lot.

/* Thanks to */

Vishalcj17
kristofpetho
kdrag0n
kerneltoast (SultanXDA)

/* Instructions */

1. Read the above. Please.
2. Flash the zip file from FK Kernel Manager. Any other installation methods are untested.

/* Downloads and links */

arter97.com
Kernel source
Telegram chat link
 
Last edited:

arter97

Recognized Developer
Oct 14, 2012
3,781
33,941
23
Seoul
/* Changelog */

r2

Display-related processes are now allowed to use the middle cores as well for better smoothness
Enabled more mremap() performance improvement that was missing from r1
LA.UM.9.14.r1-18400-LAHAINA.0 merged
LA.UM.9.16.r1-08100-MANNAR.0 merged
LA.UM.10.9.1.r1-00300-QCS610.0 merged (contains a lot of new improvements including power optimizations)
Linux v5.4.159 merged
Wi-Fi drivers updated to 2.0.8.25M
2021-11-06 security patch merged
Watermark boosting disabled to fix aggressive app killings (by Sultan)
Workaround added to fix unwanted doubles presses from the power button

r1
First stable release
 
Last edited:

rejectedjs

Senior Member
Apr 1, 2012
385
122
Holy **** this is exciting. This kernel is the one that I ran back on my OP7P and it's why I loved that phone so much. Is the 9 why you stopped development on that device?
 
  • Like
Reactions: galaxys

basboosa

New member
Mar 16, 2018
2
3
Does vendor _boot get altered after flashing kernel meaning flash back untouched backed up vendor boot to take next ota?

Was using this kernel briefly, and just updated to 11.2.9.9 (Global), had to flash stock vendor_boot, dtbo, and boot to be able to upgrade.


Anyone running this yet? If so how is it? Thinking of flashing this on stock 11.2.9.9

During my brief time using the kernel, had a minor issue whereby AUX (via USB-C) in my car wasn't working.


BTW thanks for the awesome kernel, planning to use it once wireguard support is added!
 

arter97

Recognized Developer
Oct 14, 2012
3,781
33,941
23
Seoul
Another new alpha build is up with big changes yet again.
I still have quite a few TODOs left, but I ported many changes from my OnePlus 7 Pro kernel.

Wi-Fi will behave differently with this kernel, so please let me know if you encounter Wi-Fi issues.

r1a7

Wi-Fi configuration merged with the latest CAF
Wi-Fi's rx_wakelock disabled and removed
Support for WireGuard added
Bunch of memory optimizations
Bunch of optimizations for screen and the GPU driver
 
Last edited:

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  • 18
    r2 is up, and it's a big release.

    Changelog is quite self-explanatory.

    r2
    Display-related processes are now allowed to use the middle cores as well for better smoothness
    Enabled more mremap() performance improvement that was missing from r1
    LA.UM.9.14.r1-18400-LAHAINA.0 merged
    LA.UM.9.16.r1-08100-MANNAR.0 merged
    LA.UM.10.9.1.r1-00300-QCS610.0 merged (contains a lot of new improvements including power optimizations)
    Linux v5.4.159 merged
    Wi-Fi drivers updated to 2.0.8.25M
    2021-11-06 security patch merged
    Watermark boosting disabled to fix aggressive app killings (by Sultan)
    Workaround added to fix unwanted doubles presses from the power button
    6
    Sorry to be a pest, but can someone please explain how to backup vendor_boot and the dtbo partitions, and also what are the commands to restore them when needed to restore to stock? Thanks for the help folks.

    Open terminal, become root. Then:

    $ mkdir /sdcard/disk_images

    $ dd if=/dev/block/by-name/vendor_boot_a of=/sdcard/disk_images/vendor_boot_a.img

    $ dd if=/dev/block/by-name/dtbo_a of=/sdcard/disk_images/dtbo_a.img

    And so forth. Replace '_a" with "_b" if applicable.

    'Hope this helps.
    6
    @r4p70r @thirtythr33 @l_mike There is another way via fastboot (provided of course you have the backup files). That's what I did yesterday with the help of others.

    Be on 11.2.9.9, then do the following while in fastboot:

    fastboot flash boot boot.img (this should be stock 11.2.9.9 kernel)
    fastboot flash dtbo dtbo.img
    fastboot flash vendor_boot vendor_boot.img


    You'll boot into unrooted 11.2.9.9, then you can local upgrade to 11.2.10.10 and re-root.

    If you're unsure about the slot, do fastboot getvar current-slot, then flash the correspondent commands/images accordingly.

    By the way, the "Partitions Backup & Restore" app from play store does backup both slots for each, which puts your mind at ease when you do, so you get "dtbo_a" and "dtbo_b" and so on.

    4
    Reflashing the whole ROM is not a option - it would take too much time to restore all my data.

    And your answer does not help at all.... oO Your answer is like "ah you have a problem with your windows - reinstall it and dont try to fix it"
    he mean just make "dirty" flash without wiping anything. I did that just for testing, and everything goes well
    3
    Hi Eveybody
    Interesting kernel for 1+9 ...
    But I am worried regarding vendor_boot and the dtbo partitions.
    Can I easily undo the changes if I reflash the full stock rom?
    I didn't create backups the first time so I tried to reflash the stock ROM in TWRP but it failed to mount some partitions. I had to use the MSM tool to get my phone back to stock. I now backed up the partitions (and made sure I read the post properly) and flashed this kernel again.

    Just back up your partitions using the method provided by tathagatab

    Open terminal, become root. Then:

    $ mkdir /sdcard/disk_images

    $ dd if=/dev/block/by-name/vendor_boot_a of=/sdcard/disk_images/vendor_boot_a.img

    $ dd if=/dev/block/by-name/dtbo_a of=/sdcard/disk_images/dtbo_a.img

    And so forth. Replace '_a" with "_b" if applicable.

    'Hope this helps.



    And then restore them using the method provided by xontax: https://forum.xda-developers.com/t/r1-arter97-kernel-for-oneplus-9-series.4334607/post-85669053



    Hope this helps you.
  • 41
    arter97-xda.png



    arter97 kernel for OnePlus 9 series running OxygenOS

    /* Features */

    Supports OnePlus 9 series
    Fully rebased kernel without unnecessary OnePlus code
    Latest CAF msm-5.4 kernel fully merged
    Latest Linux v5.4 subversion merged
    Latest Google’s security fix merged
    BBR as the default TCP network congestion control
    Features the latest WireGuard
    Modules support disabled for lighter kernel
    Latest Wi-Fi drivers from Qualcomm with customized config
    Built with Clang 12 and ThinLTO
    Power optimizations
    Memory management optimizations
    Latest SELinux subsystem backported from mainline
    Latest f2fs backported from mainline
    Latest BFQ I/O scheduler backported from mainline
    mmap/mremap backported from mainline for a major performance boost
    Touchscreen optimizations for lower latency
    Uses LRNG for better performance

    /* Details */

    - Fully rebased kernel without unnecessary OnePlus code -



    This kernel is not based on the stock OxygenOS kernel source provided by OnePlus. Instead, it’s based on the latest and greatest Qualcomm has to offer. Only the necessary parts from the OnePlus kernel have been cherry-picked, such as OnePlus 9 specific device drivers.

    This effectively kills all kernel modifications/optimizations from OnePlus, including the infamous app throttler.
    Due to the completely different base, this kernel will behave drastically different from other kernels, in both good and bad ways.


    - Power optimizations -


    This kernel makes some conscious decisions for reducing power consumption.

    First, the stock OnePlus configuration forces display-related processes to use the big cores exclusively.
    This configuration brings a huge power regression since it makes every frame dispatch to wake up and use the power-hungry cores.

    This kernel resets this profile to use the configuration Google recommends, which is to use the LITTLE cores exclusively instead. (Reverted in r2 as it seems like that little cores aren't enough to drive 120 Hz fluidly.)
    This kernel allows these processes to use little and middle cores (0-6), depending on the load.

    Second, this kernel disables wakelocks upon Wi-Fi’s RX unicast packet transmissions. qcom_rx_wakelock is one of the major culprits to increased idle power consumption. Although its total wakelock time is quite low, it's catched very frequently and prevents the system from entering suspend repeatedly.

    As dropping unicast or local ARP packets doesn’t pose practical issues on Android, this kernel disables qcom_rx_wakelock.

    Third, this kernel reduces the duration of the Bluetooth ISR wakelock from 2 seconds to 100ms. This was done from an observation that the average userspace response time from ISR is less than 10ms.
    My kernels have been doing this for years and no Bluetooth-related issues were reported.

    Fourth, the vibrator driver used in this kernel no longer controls the cpuidle driver. The stock kernel disables the cpuidle whenever the vibrator is used. This kernel disables it as the vibrator is not that sensitive to deadline misses.

    There are other small improvements throughout the kernel tree as well.


    - Memory management optimizations -


    This kernel disables LMKD and uses an in-kernel solution called SimpleLMK, made by kerneltoast. You can track how often SimpleLMK kicks in by monitoring:
    Code:
    /sys/module/lowmemorykiller/parameters/lmk_count

    This kernel also changes a lot related to swap and zram.

    The swap-related code has been backported from Linux v5.9 (link1, link2) to efficiently support fast swap device and allow swappiness over 100. This kernel currently sets swappiness to 160 on < 6GB of RAM, 120 on 8GB and 90 on 12GB.

    zram has been also backported from mainline Linux and further tweaked to use block device writeback. This is equivalent to the recent “RAM Plus” feature that companies have been marketing that uses the internal storage to extend RAM.

    This kernel uses zram writeback to offload idle pages (i.e., really, really unused RAM) to the internal storage. As it's extremely slow to bring pages back from UFS, writeback code works quite conservatively. It'll start to writeback pages that haven't been used for a day or two. It makes use of the hidden 2GB “last_parti” partition from the UFS storage.

    Along with zram writeback, this kernel also enables deduplication with xxHash. Each page stored in zram is checked for deduplication to further save memory. With these 2 features combined, RAM reaching 1GB is additionally saved, but your mileage may vary.

    The post boot script used in the stock ROM is also overridden and it sets the readahead to 128KB. As I/O workload under Android is mostly random, high readahead doesn’t help and only increases memory thrashing.

    This kernel also incorporates a lot of patches to reduce/optimize memory allocations used throughout the entire kernel.

    mmap/mremap code was also backported from Linux v5.10 to optimize ART (see here for more info).


    - Latest subsystems -


    This kernel backports the SELinux subsystem from mainline Linux. This includes caching improvements that drastically reduces time spent on lookups. 10K lines of code has been changed.

    This kernel also backports f2fs (Flash-Friendly File System) from mainline Linux. This includes bug fixes and performance improvements such as shorter discard latency, more optimized GC logic for Android, and checkpoint merging.

    BFQ I/O scheduler has also been backported from mainline Linux for better I/O performance.


    - LRNG -


    This kernel ditches the traditional RNG driver from the Linux kernel in favor of LRNG. See here and here for more info.

    A rudimentary throughput benchmark shows an improvement of 10.5% (keep in mind that this is only one aspect of an RNG metric).


    /* Notice */

    Only OxygenOS on Android 11 is supported.

    This kernel touches vendor_boot and dtbo partitions, meaning you'd need to restore said partitions whenever you're switching to another kernel or stock.
    Please make a back-up of these partitions. The installer doesn’t do this automatically for you. Installing the stock ROM with a full OTA restores said partitions as well.

    /* Disclaimer */

    Your warranty is now void.
    I am not responsible for bricked devices, dead SD cards,
    thermonuclear war, or you getting fired because the alarm app failed. Please
    do some research if you have any concerns about features included in this kernel
    before flashing it! YOU are choosing to make these modifications, and if
    you point the finger at me for messing up your device, I will laugh at you. Hard. A lot.

    /* Thanks to */

    Vishalcj17
    kristofpetho
    kdrag0n
    kerneltoast (SultanXDA)

    /* Instructions */

    1. Read the above. Please.
    2. Flash the zip file from FK Kernel Manager. Any other installation methods are untested.

    /* Downloads and links */

    arter97.com
    Kernel source
    Telegram chat link
    18
    r2 is up, and it's a big release.

    Changelog is quite self-explanatory.

    r2
    Display-related processes are now allowed to use the middle cores as well for better smoothness
    Enabled more mremap() performance improvement that was missing from r1
    LA.UM.9.14.r1-18400-LAHAINA.0 merged
    LA.UM.9.16.r1-08100-MANNAR.0 merged
    LA.UM.10.9.1.r1-00300-QCS610.0 merged (contains a lot of new improvements including power optimizations)
    Linux v5.4.159 merged
    Wi-Fi drivers updated to 2.0.8.25M
    2021-11-06 security patch merged
    Watermark boosting disabled to fix aggressive app killings (by Sultan)
    Workaround added to fix unwanted doubles presses from the power button
    15
    After using the kernel myself and daily driving for few days and monitoring how the kernel behaves, I now feel comfortable to mark it stable.

    r1 is released.

    The original post is re-written to feature what's special with this kernel.
    Please take your time and re-read the original post.
    10
    /* Changelog */

    r2

    Display-related processes are now allowed to use the middle cores as well for better smoothness
    Enabled more mremap() performance improvement that was missing from r1
    LA.UM.9.14.r1-18400-LAHAINA.0 merged
    LA.UM.9.16.r1-08100-MANNAR.0 merged
    LA.UM.10.9.1.r1-00300-QCS610.0 merged (contains a lot of new improvements including power optimizations)
    Linux v5.4.159 merged
    Wi-Fi drivers updated to 2.0.8.25M
    2021-11-06 security patch merged
    Watermark boosting disabled to fix aggressive app killings (by Sultan)
    Workaround added to fix unwanted doubles presses from the power button

    r1
    First stable release
    9
    Another new alpha build is up with big changes yet again.
    I still have quite a few TODOs left, but I ported many changes from my OnePlus 7 Pro kernel.

    Wi-Fi will behave differently with this kernel, so please let me know if you encounter Wi-Fi issues.

    r1a7

    Wi-Fi configuration merged with the latest CAF
    Wi-Fi's rx_wakelock disabled and removed
    Support for WireGuard added
    Bunch of memory optimizations
    Bunch of optimizations for screen and the GPU driver