Kernel Info
Here is some info on my Kernel builds
Brief overview:
Regular builds (Included in some roms)- based on Lineage (with many improvements from Omni), This has eas, so don't use the interactive cpu governor.
the one for omni is the same except the ramdisk has been optimized for omni so it will boot on it
Info on kernel settings:
CPU governors (the recommended ones), source
http://androidmodguide.blogspot.com/p/blog-page.html?m=1
OnDemand:
Ondemand is one of the original and oldest governors available on the linux kernel. When the load placed on your CPU reaches the set threshold, the governor will quickly ramp up to the maximum CPU frequency. It has excellent fluidity because of this high-frequency bias, but it can also have a relatively negative effect on battery life versus other governors. OnDemand was commonly chosen by smartphone manufacturers in the past because it is well-tested and reliable, but it is outdated now and is being replaced by Google's Interactive governor.
Interactive:
don't use this, terrible on eas
Alucard
A favorite choice and one of the original governors that Alucard_24 made. Alucard is based on ondemand but has been heavily tweaked to bring better battery life and performance. It has been known to be battery friendly without sacrificing much performance.
Bioshock
A mix of ConservativeX and Lionheart. Good balance between battery savings and performance.
ConservativeX:
Also developed by Imoseyon (feat. briefly in the Lean Kernel for Galaxy Nexus), the ConservativeX governor behaves like the Conservative governor with the added benefit of locking the CPU frequency to the lowest interval when the screen is off. This governor may additionally perform hotplugging on CPU1, but there is no documentation to confirm that suspicion at this time.
Conservative:
This governor biases the phone to prefer the lowest possible clockspeed as often as possible. In other words, a larger and more persistent load must be placed on the CPU before the conservative governor will be prompted to raise the CPU clockspeed. Depending on how the developer has implemented this governor, and the minimum clockspeed chosen by the user, the conservative governor can introduce choppy performance. On the other hand, it can be good for battery life
ConservativeX
Also developed by Imoseyon (feat. briefly in the Lean Kernel for Galaxy Nexus), the ConservativeX governor behaves like the Conservative governor with the added benefit of locking the CPU frequency to the lowest interval when the screen is off. This governor may additionally perform hotplugging on CPU1, but there is no documentation to confirm that suspicion at this time.
Darkness
It's based on nightmare but more simple and fast, basic configs but very complex structure. It is an updated version of the nightmare gov, so far it is quite stable in tests,
nightmare info:
A PegasusQ modified, less aggressive and more stable. A good compromise between performance and battery. In addition to the SoD is a prevention because it usually does not hotplug.
Pegasusq info:
The Pegasusq / d is a multi-core based on the Ondemand governor and governor with integrated hot-plugging. It is quite stable and has the same battery life as ondemand. Ongoing processes in the queue, we know that multiple processes can run simultaneously on. These processes are active in an array, which is a field called "Run Queue" queue that is ongoing, with their priority values arranged (priority will be used by the task scheduler, which then decides which process to run next).
To ensure that each process has its fair share of resources, each will run for a certain period and will eventually stop and then again placed in the queue until it is your turn again. If a program is terminated, so that others can run the program with the highest priority in the current queue is executed.
Despair
It is a tweaked conservative governor with a couple extra values exposed, it tends to be a bit more conservative with battery than the conservative governor by default. Developed by DespairFactor.
ElementalX
ElementalX is basically a multiphase Ondemand governor that aims to achieve the best balance between battery life and performance. By default, it is more conservative than Ondemand as it does not ramp up often for most phone activities. If there is a graphics load detected, the governor will switch to a two-phase Ondemand behaviour where different max frequencies are used depending on the load increase. ElementalX comes with input boost enabled by default lowering the sampling rate and increasing the frequency to improve responsiveness.
Impulse
An improved version of interactive modified by neobuddy89. Impulse aims to have a balance between battery and performance just like interactive but has some tweaks to save battery.
Lionheart
Lionheart is a conservative-based governor which is based on samsung's update3 source.
The tunables (such as the thresholds and sampling rate) were changed so the governor behaves more like the performance one, at the cost of battery as the scaling is very aggressive.
Lionfish
The Lionfish governor combines traits of the conservative, ondemand, and interactive governors. It is designed to maximize battery life without noticeably impacting performance. It responds quickly to heavy loads (similar to ondemand and interactive) while staying within the region of optimal CPU performance per watt. With moderate loads, it periodically votes to raise, maintain, or decrease the frequency. When there are enough votes to change the frequency, it is ramped up and down gradually. The voting mechanism reduces frequency jitter compared to ondemand and conservative. squid2's testing had found that this governor uses moderate frequencies (where efficiency is optimal) more effectively than interactive, ondemand, and conservative. This improved frequency distribution results in a moderate reduction in CPU power consumption while maintaining responsiveness comparable to the interactive governor.
Nebula
A port of the Interactive governor based on msm-4.4 sources with some mods for the HTC 10, preserving the excellent balance between performance and battery life found in many other Interactive based govs. It originated from Eliminater74's Nebula kernel and was a popular choice prior to the introduction of EAS scheduling to the kernel.
Smartmax
By default this is configured for battery saving, so this is NOT a gaming or benchmark governor! Additionally, to make it "snappy", smartmax has "touch poke". So input events from the touchscreen will boost the cpu for a specific time to a specific frequency. Developed by XDA user Maxwen.
Wheatley
This governor is build on “ondemand” but increases the C4 (the sleep state) state time of the CPU and doing so trying to save juice. So the results show that Wheatley works as intended and ensures that the C4 state is used whenever the task allows a proper efficient usage of the C4 state. For more demanding tasks which cause a large number of wakeups and prevent the efficient usage of the C4 state, the governor resorts to the next best power saving mechanism and scales down the frequency. So with the new highly-flexible Wheatley governor one can have the best of both worlds. Obviously, this governor is only available on multi-core devices.
Wheatley is a more performance orientated governor as it scales more aggressively than ondemand and sticks with higher frequencies.
Yankactive
A slightly modified interactive based governor by Yank555.lu. It has battery tweaks added onto it so expect better battery life! Based on user reports, this governor behaves more battery friendly than the original interactive governor without sacrificing performance.
I recommend using schedutil for everyday usage, wheatley for performance. and Impluse for battery life
GPU governors (the recommended ones) source
http://androidmodguide.blogspot.com/p/blog-page.html?m=1
simple_ondemand: As the name implies, it is a simpler version of the CPU governor ondemand. simple_ondemand will ramp up the frequency when a load is detected. It has a good balance between performance and battery savings.
msm-adreno-tz: The default GPU governor used by Qualcomm for their adreno GPUs. It is based on the ondemand governor but is biased towards performance, therefore it should give better performance in games but less battery life.
I recommend using simple_ondemand for regular usage due to the battery savings
I/O schedulers: (the recommended ones)
source-
http://androidmodguide.blogspot.com/p/io-schedulers.html?m=1
Deadline:
The goal of the Deadline scheduler is to attempt to guarantee a start service time for a request. It does that by imposing a deadline on all I/O operations to prevent starvation of requests. It also maintains two deadline queues, in addition to the sorted queues (both read and write). Deadline queues are basically sorted by their deadline (the expiration time), while the sorted queues are sorted by the sector number.
Before serving the next request, the Deadline scheduler decides which queue to use. Read queues are given a higher priority, because processes usually block on read operations. Next, the Deadline scheduler checks if the first request in the deadline queue has expired. Otherwise, the scheduler serves a batch of requests from the sorted queue. In both cases, the scheduler also serves a batch of requests following the chosen request in the sorted queue.
Benefits:
- Nearly a real-time scheduler.
- Excels in reducing latency of any given single I/O
- Best scheduler for database access and queries.
- Does quite well in benchmarks, most likely the best
- Like noop, a good scheduler for solid state/flash drives
Disadvantages:
- If the phone is overloaded, crashing or unexpected closure of processes can occur
The bottom line: A good all-round scheduler. If you want good performance, you should try deadline.
Noop:
Inserts all the incoming I/O requests to a First In First Out queue and implements request merging. Best used with storage devices that does not depend on mechanical movement to access data (yes, like our flash drives). Advantage here is that flash drives does not require reordering of multiple I/O requests unlike in normal hard drives.
Benefits:
- Serves I/O requests with least number of CPU cycles.
- Best for flash drives since there is no seeking penalty.
- Good data throughput on db systems
- Does great in benchmarks
- Is very reliable
Disadvantages:
- Reducing the number of CPU cycles corresponds to a simultaneous decline in performance
- Not the most responsive I/O scheduler
- Not very good at multitasking (especially heavy workloads)
The bottom line: Modern smartphones now use Noop as the default scheduler due to the fact that it works quite well with flash based storage. However older devices may experience slower performance when selected. If you want a very simple I/O scheduler algorithm (because of battery life or latency reasons), you can select this.
CFQ:
Completely Fair Queuing scheduler maintains a scalable per-process I/O queue and attempts to distribute the available I/O bandwidth equally among all I/O requests. Each per-process queue contains synchronous requests from processes. Time slice allocated for each queue depends on the priority of the 'parent' process. V2 of CFQ has some fixes which solves process' i/o starvation and some small backward seeks in the hope of improving responsiveness.
Benefits:
- Has a well balanced I/O performance
- Excellent on multiprocessor systems
- Regarded as a stable I/O scheduler
- Good for multitasking
Disadvantages:
- Some users report media scanning takes longest to complete using CFQ. This could be because of the property that since the bandwidth is equally distributed to all i/o operations during boot-up, media scanning is not given any special priority.
- Jitter (worst case delay) can sometimes be very high because the number of competing with each other process tasks
- Under constant load, the phone will experience increased I/O latency due to the way how the scheduler tries to create 'fairness'
The bottom line: One of the best all-rounder I/O schedulers available. CFQ is better suited for traditional hard disks, however it may give better throughput under some situations.
BFQ:
Instead of time slices allocation by CFQ, BFQ assigns budgets. Disk is granted to an active process until it's budget (number of sectors) expires. BFQ assigns high budgets to non-read tasks. Budget assigned to a process varies over time as a function of it's behavior.
Benefits:
- Has a very good USB data transfer rate.
- The best scheduler for playback of HD video recording and video streaming (due to less jitter than CFQ Scheduler, and others)
- Regarded as a very precise working Scheduler
- Delivers 30% more throughput than CFQ
- Good for multitasking, more responsive than CFQ
Disadvantages:
- Not the best scheduler for benchmarks
- Higher budgets that were allocated to a process that can affect the interactivity and bring with it increased latency.
The bottom line: There are better schedulers out there that will perform better than BFQ. It is quite a complex scheduler that is better designed for traditional hard disks.
SIO (Simple):
Simple I/O aims to keep minimum overhead to achieve low latency to serve I/O requests. No priority queue concepts, but only basic merging. SIO is a mix between noop & deadline. No reordering or sorting of requests.
Benefits:
- It is simple and stable.
- Minimized starvation for inquiries
Disadvantages:
- Slow random write speeds on flash drives as opposed to other schedulers.
- Sequential read speeds on flash drives are not as good as other IO schedulers
- Not the best scheduler for benchmarks
The bottom line:It is a good all-round scheduler. People who want better performance should avoid using this.
FIOPS (Fair IOPS):
This new I/O scheduler is designed around the following assumptions about Flash-based storage devices: no I/O seek time, read and write I/O cost is usually different from rotating media, time to make a request depends upon the request size, and high through-put and higher IOPS with low-latency. FIOPS (Fair IOPS) ioscheduler tries to fix the gaps in CFQ. It's IOPS based, so it only targets for drive without I/O seek. It's quite similar like CFQ, but the dispatch decision is made according to IOPS instead of slice.
Benefits:
- Achieves high read and write speeds in benchmarks
- Faster app launching time and overall UI experience
Disadvantages:
- Not the most responsive IO scheduler (Can make phone lag)
- Not good at heavy multitasking
The bottom line: Most people who use FIOPS will get a noticeable performance improvement. However, you may get issues with scrolling and general lags.
ZEN
ZEN is based on the Noop, Deadline and SIO I/O schedulers. It's an FCFS (First come, first serve) based algorithm, but it's not strictly FIFO. ZEN does not do any sorting. It uses deadlines for fairness, and treats synchronous requests with priority over asynchronous ones. Other than that, it's pretty much the same as Noop blended with VR features.
VR:
Unlike other scheduling software, synchronous and asynchronous requests are not handled separately, but it will impose a fair and balanced within this deadline requests, that the next request to be served is a function of distance from the last request.
Benefits:
- Well rounded IO Scheduler
- Very efficient IO Scheduler
- More stable than VR, more polished
Disadvantages:
- Performance variability can lead to different results (Only performs well sometimes)
The bottom line: It is pretty much a better version of VR, performs quite well and is stable. Overall this is a good choice for most smartphones.
SIOplus
Based on the original SIO scheduler with improvements. Functionality for specifying the starvation of async reads against sync reads; starved write requests counter only counts when there actually are write requests in the queue; fixed a bug).
Benefits:
- Better read and write speeds than previous SIO scheduler
Disadvantages:
- Fluctuations in performance may be observed
The bottom line: If you liked SIO, you will like SIOplus. It performs slightly better in some usage case scenarios, but performance seekers should look else where
Tripndroid
A new I/O scheduler based on Noop, deadline and vr and meant to have minimal overhead. Made by TripNRaVeR
Benefits:
- Great at IO performance and everyday multitasking
- Well rounded and efficient IO scheduler
- Very responsive I/O scheduler (Compared to FIOPS)
Disadvantages:
- Performance varies between different devices (Some devices perform really well, I haven't tested it much on zl1)
The bottom line: Tripndroid isn't really common, there are other schedulers you can choose which may perform similar or better
Maple
Maple is based on the Zen and Simple I/O schedulers. It uses ZEN's first-come-first-serve style algorithm with separate read/write requests and improved former/latter request handling from SIO. Maple is biased towards handling asynchronous requests before synchronous, and read requests before write. While this can have negative aspects on write intensive tasks like file copying, it slightly improves UI responsiveness. When the device is asleep, maple increases the expiry time of requests so that it can handle them more slowly, causing less overhead.
Benefits:
- Well rounded IO Scheduler
- Very efficient IO Scheduler
Disadvantages:
- Performance varies between different devices (Some devices perform really well)
The bottom line: This is still a very new I/O scheduler which should perform slightly better than ZEN. It will continue to improve with more development.
Summary:
Use noop or sioplus for battery life, bfq or Maple for multitasking, fiops for gaming, sioplus or cfq for stability, and deadline for all around performance
CONTINUED ON THE NEXT POST
first of all congratulations for the great work you are carrying on. I'm currently testing the regular kernel and noticed the new up_threshold and down_thresold settings on the CPU board. I tried in op but did not find anything about it. If I understand that the use of these new parameters should serve to turn on and off the second small cluster core in relation to the load of the root core. right? I think with this new implementation you will have a good battery saver. You could better explain how this feature works and how to configure it best. Thanks for the great work??
