I searched for answers but didn't get satisfactory results, so I wanna ask my G2 peeps.
CM7 has an OC daemon, right?
Since it does, is SetCPU still needed?
How does one configure the OC daemon with profiles for screen off, battery>50% etc etc?
I am running CM7.1
convolution said:
I searched for answers but didn't get satisfactory results, so I wanna ask my G2 peeps.
CM7 has an OC daemon, right?
Since it does, is SetCPU still needed?
How does one configure the OC daemon with profiles for screen off, battery>50% etc etc?
I am running CM7.1
Click to expand...
Click to collapse
CM7 does have an OC daemon but it does not have profile settings like SetCPU. Most feel that using profiles kills the battery faster than not using profiles as the device is having to poll the system so frequently. If you just set the min and max speeds, you'll be fine.
Sent from my HTC Vision using XDA App
Just a question though. What does ONDEMAND govenor do?
Like when the phone is not doing anything, the phone will automatically go to the minimum clockspeed, and if you are playing intense games, the phone will max out?
Does that mean when the phone is screen off, the clockspeed will be minimum?
Because the only reason I have setcpu is to set the profile so it goes to 500/200 mhz screen off...
I think the CM7 included OC/UC manager is pretty darn good. I wouldn't worry about using SetCPU it'll just interfere.
convolution said:
Just a question though. What does ONDEMAND govenor do?
Like when the phone is not doing anything, the phone will automatically go to the minimum clockspeed, and if you are playing intense games, the phone will max out?
Does that mean when the phone is screen off, the clockspeed will be minimum?
Click to expand...
Click to collapse
Yes. You can see the exact way that each governor works, but that's pretty much the case with ONDEMAND.
convolution said:
CM7 has an OC daemon, right?
Click to expand...
Click to collapse
No, there is no background process (daemon) controlling the cpu min/max.
It only applies the settings at boot, aside from that, it does nothing.
on our devices, there are three (main) files that effect the cpu overclocking:
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
writing a value to these files will make the cpu do what you want. (which is what the CM7 controls do)
You can still use SetCPU if you want... all it does is write the values to these files & the kernel handles the rest.
For example, it can be a slightly more convenient method of cranking up the max frequency if you are about to play a particularly cpu intensive game.
I also find SetCPU handy to do a quick check on the "time in state" & "memory" stats
If you want to use the SetCPU profiles, then, as OriginalGabriel pointed out, it could lead to slightly increased battery usage as SetCPU has to remain running in the background monitoring the variables.
If you don't use the profiles, then SetCPU won't consume any battery.
virtuous_oc, andrev_oc & ilwt_oc are a background process (daemon) that react to a change in screen state & write their defined settings to the above mentioned files.
The difference:
SetCPU runs in Android userspace & has to wait for the android system to send out a broadcast intent that the screen has been turned on/off before it can react & write the values to the files mentioned above.
The OC daemons do not run in userspace & detect the change in screen state at a kernel level... they will have written the values to the files well before the intent gets broadcast.
convolution said:
Just a question though. What does ONDEMAND govenor do?
Like when the phone is not doing anything, the phone will automatically go to the minimum clockspeed, and if you are playing intense games, the phone will max out?
Does that mean when the phone is screen off, the clockspeed will be minimum?
Because the only reason I have setcpu is to set the profile so it goes to 500/200 mhz screen off...
Click to expand...
Click to collapse
The governor controls how the cpu steps up or down the available frequencies based on the current load.
Each of the governors use a slightly different algorithm in how the cpu steps up or down. (within Max & Min as specified by scaling_max_freq & scaling_min_freq)
The well known governors from the mainline Linux kernel:
Ondemand: at the onset of load, jumps straight to max frequency & then steps down through the frequency table.
Conservative: steps up through the frequencies & back down.
Performance: this governor just keeps the cpu at scaling_max_freq & doesn't scale down
Powersave: this keeps the cpu at scaling_min_freq & doesn't scale up
Also, there are a number of governors that have come about from the Android community, I don't have the time right now to write about all the others that I know of... but can do at a later stage if it helps?
The important thing to note, is that unless you device is staying awake when the screen turns off, the screen off profiles are somewhat pointless, as the cpu effectively gets turned off.
Sorry bout the wall of text... am at work & typed it out in a bit of a hurry... hope it all makes sense
Its not needed but u can use it
Sent from my HTC Vision using xda premium
INTRODUCTION -
This guide is intended to help those who are coming to the Kernel KT747 by @ktoonsez. This thread and the subsequent Posts are intended to be as a Guide for users that are new to this Kernel and its Tweaker. Complete credit for the development of the Kernel goes to @ktoonsez. You can find his Kernel thread bellow.
KT747 - SGH-T999 Touchwiz & AOSP - Thread by Ktoonsez
Older Builds of the Kernel - Thread by @LuigiBull23
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INTRODUCTION -
There are quiet a few times when users have asked for the choice, usage as well as definition of various parameters of the Governers and Schedulers. Hence I decided to write this guide as a way to help the users understand the various basic terms and parameters. I am perfectly aware that there are quiet a few excellent guides on the different ICS & JB Governers. As a matter of fact, I have linked to some of them. So eventhough I have given basic information on Governers in this kernel, it is not my primary purpose to serve this as the ultimate guide on that subject.
This is a living guide and given vastness of the subject, I will continue to modify the OP as well as subsequent posts.
Disclaimer:
I am not responsible if you end up with expensive brick. Read the guide as much as you want and ask questions before proceeding with overclocking.
Overclocking and undervolting is highly debatable, some say its good and some say its bad... so its upto you to proceed further. While on the word of Caution – I have personally managed to Smoke (I mean literally physically cause smoke) from a Tablet by testing SetCPU Overclocking on it.
Here’s another nice detail on why Friends don't let Friends do extreme Overclock or Undervolt! post by @dorimanx, the developer of the other excellent kernel.
PURPOSE / INTENT -
The intent of this thread is to help new users learn, and act as reference for more knowledgeable users, on the Governers & Schedulers incorporated into this Kernel. Another Purpose is to help those who are new to Overclocking & undervolting in general.
There are quite a few good guides on this forum regarding Overclocking. So Rather than writing one myself, I am going to refer to one by @bala_gamer, who has written a pretty comprehensive guide for the International version of Galaxy SIII. Even though the hardware is different between that phone and this one, the guide is good enough for those who are starting down this path and want to get basic understanding.
Another intentional purpose of this thread is to provide a platform to discuss Overclocking and undervolting settings for SGH-T999 specific version. Given that I wish offer to the experts a platform to discuss, in interest of New users and their phone, I have been careful enough to include warnings and footnotes where possible.
WHAT DO I GET BY OVERCLOCKING/UNDERVOLTING -
In short, modern Microprocessors, to a certain degree have a range of Operational frequency steps. Also especially for multiprocessor devices, it is possible to control when a processor comes into play and when it does not. Now, the main question that comes to mind is, why would you want to turn off processors? Well, consider this. It’s Kind of an analogy like a car engine. On a 6 Cylinder engine, the fuel consumption is a lot more. But if you were to turn off 2 out of the 6 cylinders, then there is still power to drive and fuel consumption is lower. Similarly, with one of the processor turned off, battery drain is reduced not to mention heat generation.
For a given processor, by design the higher the frequency it operates, the more raw power you have available to run applications. Typically on some of the previous generation single processor phones, its not possible to run Angry Birds or other games unless you run the processor consistently at its maximum operating frequency. So users may choose to Overclock the phone in order to run such Apps.
On the flip side, if you are a light user, then it will benefit if you turned off the other processor(s). This saves the battery. Given there are multitudes of Frequency steps, if the processor operates at lower frequency, there is less heat generated and less battery used. Before I proceed further, I am respectfully Quoting Castle_Bravo from here. He has summarized perfectly what I’d have said otherwise.
castle_bravo said:
In the pc world we have things like clock speeds, latency, read speed, bus speeds and things of this nature. Right now im going to talk about over clocking a processor, whether it's a gpu I or a cpu. When we over clock these devices, meaning make them go faster than originally rated by the manufacturer using software of any kind, these devices will also work harder. The faster the clock speed the hotter the component gets and the shorter it's life span is due to thermal stresses. Hence our manufacturer rating of speeds.
There are two ways to combat heat; heat is the main enemy in any high powered system (do a YouTube search of running a cpu with no heart sink). Add more cooling via more hardware and lower voltages applied to the component. Adding more cooling hardware is the preferred method. This is the best way because now that the component is working faster at the same temperatures it was at before on stock clock speeds it is, in terms of math, working LESS. This applies to ram, video card, cpu's and the like.
Typically, as you raise clock speeds you also have to RAISE voltages in order to keep it stable. There are exceptions like in a VERY minor over clock you can actually lower voltages. The trade off here is that with the larger cooling equipment and the faster clock speeds the processor will spend less time at peak load and return to idle faster. If set up correctly you can actually draw less cumulative power using higher voltages. This is assuming temperatures are the same for both scenarios of stock clock and over clock. BUT, more power applied equals more heat. Now, as we raise clock speeds and raise our voltage, we try to be on the edge of not enough. Because what does more power mean? More heat. And what does more heat mean? Less component life. Not only that but the components have a "healthy" voltage band due to tolerances in its manufacture so we don't want to exceed that.
We undervolt mainly to protect the equipment. Secondary is battery savings. We do not have the option of installing more hardware to cool our devices so all we can do is lower voltages. Lowering voltages will help keep the component cool because it is pulling less electrons. More power = more heat. the cpu will become unstable and make it work harder, which is counter productive and will have a reverse effect. So take that voltage too far down and now the component doesn't have enough power to perform its job properly or efficiently, making it work HARDER. What happens when a component works harder? It heats up. So we can actually have a reverse effect from our intended power savings.
Click to expand...
Click to collapse
Last But Not Least, here’s a nice Q&A by XDA User @droidphile for further reading. Although it is written for the Galaxy S2, quite a few parts do apply as this device too has dual core. Since that’s another SoC, apply the settings with caution if you at all wish to apply from that post.
Implementation of Overclocking & Undervolting by using KTweaker -
Given that Ktoonsez has an excellent app for this kernel; my intention is to provide a way for you to make the best usage of the same.
By default, when the kernel is freshly installed and you open the app for the first time, there should not be any error messages of any kind. The App settings are not permanent. So every time you re-boot the phone, you are restored to original Defaults. This is a great way to test out various settings to see if they work out or turn the phone into slowpoke.
As you can see in the screen shot, there are 7 major options.
GENERAL – This is the main setting area. This is where you control the phone’s operation and other settings around how it behaves. We will go into great details later on.
VOLTAGES – This allows you to control the CPU operating voltage at a given Frequency step. It plays a significant role when you are undervolting or Overclocking.
EXTRAS – Unlike the name, this section contains quite a few important settings that modify the phone’s behavior. Specifically how the phone reacts when the screen is turned off or when you are Navigating or charging the phone.
SET OPTIONS ON BOOT – As the name suggests, you get to choose if the settings you have changed are applied after you restart or not. Also if you choose to, you can also specify a time duration after Restart before your settings get applied.
BACKUP PREFS TO SDCARD – This simply allows you to make a backup of your settings to the internal SD Card. The path is /SDCARD/KTWEAKER/. You can also name the settings optionally.
RESTORE PREFS FROM SDCARD – As the name suggests, you can re-load your backed up settings. Comes in handy if you have one set of settings that really work and you want to experiment further.
LOAD DEFAULTS – This option simply sets all the settings to the value KTOONSEZ has set up in the kernel as initial values.
GENERAL SECTION -
This is perhaps the main section of the Kernel Controls. In this section you can choose wide variety of options that directly determine the performance of the phone as well as Battery life as a result.
There are several sub-menus as follows. As you can see in the screen-shot, there is a small comment on what the section does.
1. ENABLE OC STEPS
2. LOCK FREQUENCIES – There’s a little sub-section to choose minimum and maximum operating frequencies.
3. I/O SCHEDULERS
4. I/O SCHEDULER ADJUSTMENTS
5. CPU GOVERNORS
6. CPU GOVERNOR ADJUSTMENTS
7. AUTO HOTPLUG
1. ENABLE OC STEPS -
This is a simple Check box to enable Overclocking. Select this only if you are going to overclock. By doing so, you get higher range of frequencies to choose for the Minimum and Maximum frequencies. Do note, just because it lets you specify higher frequencies, does not mean you can set to the highest value. Permanently operating at Overclocked frequency may cause physical damage to your phone. Remember Qualcomm has set 1500 MHZ as the normal operating frequency for this CPU.
2. LOCK FREQUENCIES -
This is again a Check box that effectively pegs the operating frequencies to within the Range as specified by the Minimum Frequency and Maximum Frequency sliders.
The two sliders that are part of this section need to be set after very careful consideration. If you set the minimum frequency too low, then you run the risk of a sluggish and unresponsive phone when there are no apps running. For the maximum frequency, remember higher the frequency, more heat will be produced. Also the battery will drain faster. So give it some thought before setting the limits. Choose the values based on whether you are looking to save battery or get high performance and responsiveness.
Note – A side note on this, the CPU is actually located in the back, bellow the battery compartment. So you will notice the heat in that section. If you happen to have a bumper case on the phone, you won't notice actual temperature unless the phone is really hot.
7. AUTO HOTPLUG
This is a simple Checkbox that enables Hot-Plugging support. Hotpluging is a concept borrowed from Server Linux and is applicable to Android in the same manner. In short, it allows for CPUs being removed from Service or added to service on the fly, without needing OS level Restart. Effectively this, gives the kernel a choice to Take CPU Cores offline or bring them online. Some of the Governors we discussed above already support hotplugging. This checkbox ensures support for the remaining Governors.
3. I/O SCHEDULER –
Scheduler Guide Link
This menu offers a choice of all the android Schedulers available in this kernel.
Given that there are so many excellent guides on the individual Schedulers, I do not wish to provide the same information again. (Besides this is indeed a vast topic by itself.) So without going to specific details, I am going to summarize what it means from a layman's point of view. For those with more technical inclination, I have provided a link to read further on each scheduler.
Think of an I/O Scheduler like an executive assistant to the Disc or storage of the phone. Just like the assistants, it effectively manages the disc reads or writing to it for all the processes. In particular, it determines what process gets prioritized and/or bandwidth. You have to understand; that each app you run has its own process as well as child processes it triggers. In addition, the OS too has its own processes that monitor various aspects of the phone. Effectively these are all the processes competing for the reading or writing. Based on that knowledge, you can choose whatever works best for your usage pattern. Later on I will be providing some sample settings to get you started.
Noop:
The noop scheduler is the simplest of them. It is best suited for Cell phone storage since it is flash media. As the flash drives do not require rearrangement of the I/O requests, the data that come first is written first (First in First Out). It's basically not a real scheduler, as it leaves out the scheduling of the hardware.
Benefits:
- Adds all incoming I / O requests in a first-come-who-first-served queue and implements requests with the fewest number of CPU cycles, so also battery friendly
- Is suitable for flash drives because there is no search errors
- Good data throughput on db systems
- Is nearly a real-time scheduler.
- Characterized by reducing the waiting time of each process from - best scheduler for database access and queries.
- Bandwidth requirements of a process, eg what percentage CPU is used is easy to calculate.
Disadvantages:
- If the system is overloaded, it may lose a set of processes, and is not as easy to predict
- Reducing the number of CPU cycles corresponds to a simultaneous decline in performance.
Deadline:
This scheduler has the goal of reducing I/O wait time of a process. This is done using the block numbers of the data on the drive. This also controls how outlying block numbers are processed, each request receives a maximum delivery time. This is in very popular like BFQ and Deadline:
Benefits:
- Is nearly a real-time scheduler.
- Characterized by reducing the waiting time of each process from - best scheduler for database access and queries.
- Bandwidth requirements of a process, eg what percentage does a CPU is easy to calculate.
- noop is ideal for flash drives
Disadvantages:
- If the system is overloaded, can go a lost set of processes, and is not as easy to predict. It is indeed better than the BFQ, but VR is even better.
ROW:
Reference - http://lwn.net/Articles/509829/
Read Over Write Scheduler. This scheduler ignores or backpedals the disc write operations, giving higher priority to the Read Operations.
Mobile devices prefer user experience; hence, the READ IO requests get as much priority as possible. The main idea is, if there are READ requests in pipe - dispatch them but don't delay the WRITE requests too much.
All the incoming requests are kept in multiple queues according to their priority. The dispatching of requests is done in a Merry-Go-Round fashion with a different slice of time for each queue.
Presently there are 6 types of queues the requests are parked in
[FONT="]- [/FONT]High priority READ queue
[FONT="]- [/FONT]High priority Synchronous WRITE queue
[FONT="]- [/FONT]Regular priority READ queue
[FONT="]- [/FONT]Regular priority Synchronous WRITE queue
[FONT="]- [/FONT]Regular priority WRITE queue
[FONT="]- [/FONT]Low priority READ queue
If in a certain dispatch cycle one of the queues was empty and didn't use its time, that queue will be marked as "un-served". For Ex. While in the middle of executing requests of Queue Y, a request comes to queue X (X having more priority over Y), and was un-served in the previous cycle. Then queue X will be preempted over queue Y. This won't restart the cycle. Once queue Y is done with its request, scheduler will go back to X, and allow it to finish it's request, before proceeding with resto fo the queues in the cycle.
For READ request queues idling is allowed to give the application(s) a chance to add more requests. The idling is enabled if the application is making requests in rapid succession.
ROW scheduler will support special services for memory cards that
support High Priority Requests. In addition it will support rescheduling of interrupted requests. For example, while working on a long write request, a sudden high priority read request comes in, the scheduler will inform the device and the device can stop the write request to serve the high priority read request. In such a case the device may send back the interrupted write request so that the scheduler will send it later according to the scheduler policy.
CFQ:
CFQ (Completely Fair Queuing) is similar to the Deadline. It maintains a scalable continuous Process-I/O The available I/ O bandwidth is used fairly and evenly to all I/O requests to distribute. It creates a statistics of blocks and processes. This is then used to guess when the next block is requested by what process, ie each process queue contains requests of synchronous processes, which in turn is dependent upon the priority of the original process. There is a second version with some fixes, such as allowing the request to starve, and some small search backward integrated to improve the responsiveness.
Benefits:
- It has the goal of a balanced I/O performance to deliver
- The easiest way one set
- Excellent on multiprocessor systems
- Best performance of the database after the deadline
Disadvantages:
- Some reported user that the media scanning would take very long time
- The fair and even distribution of bandwidth can cause delays in the boot process.
- Jitter (worst case delay) can be caused sometimes because of the number of competing with each other process tasks
BFQ:
Requests divided into time segments as the CFQ, but on a budget. The flash drive will be granted an active process until it has exhausted its budget (number of sectors on the flash drive).
Benefits:
- Has a very good USB data transfer rate.
- Be 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
FIOPS:
Fair, Efficient Flash I/O Scheduler is geared for the modern Flash based storage media well. I haven’t been able to find a lot of documentation for this. Will keep looking.
SIO:
It aims to achieve with minimal effort at a low latency I / O requests. Not a priority to put in queue, instead simply merge the requests. This scheduler is a mix between the noop and deadline. There is no conversion 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, not as good
V(R):
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. It is a very good scheduler with elements of the deadline scheduler. He will probably be the best for MTD Android devices. It also makes the most out of the benchmark points, but is also unstable scheduler, because its performance can fluctuates below or above average.
Benefits:
- Is the best scheduler for benchmarks
Disadvantages:
- Performance variability can lead to different results
- Very often unstable
ZEN:
This Scheduler is actually based on a combination of NOOP, SIO & VR Schedulers. This scheduler combines Synchronous & Asynchronous requests with same priority. It uses a deadline in order to derive or determine priority of a process.
FIFO:
First in First Out Scheduler. As the name says, it implements a simple priority method based on processing the requests as they come in.
4. I/O SCHEDULER ADJUSTMENTS
Ref -
https://www.kernel.org/doc/Documentation/block/
http://www.linux-mag.com/id/7572/
http://algo.ing.unimo.it/people/paolo/disk_sched/description.php
The Scheduler Adjustments are parameters that determine how the selected Scheduler behaves. Needless to say the list of parameters in this menu will change depending on which Scheduler you chose in the previous step. The screenshot depicts parameters for the ROW Scheduler. Even though there are quite a few Schedulers available in this kernel, parameters of some of them tend to be similar in effect. Hence I have combined the Schedulers whose parameters are similar.
[FONT="] Deadline, SIO and Zen: [/FONT][FONT="]
fifo_batch: This parameter controls the maximum number of requests per batch.[/FONT][FONT="]It tunes the balance between per-request latency and aggregate throughput. When low latency is the primary concern, smaller is better (where a value of 1 yields first-come first-served behavior). Increasing fifo_batch generally improves throughput, at the cost of latency variation. [/FONT]The default is 16.[FONT="]
front_merges: A request that enters the scheduler is possibly contiguous to a request that is already on the queue. Either it fits in the back of that request, or it fits at the front. Hence it’s called either a back merge candidate or a front merge candidate. Typically back merges are much more common than front merges. You can set this tunable to 0 if you know your workload will never generate front merges. Otherwise leave it at its default value 1.
[/FONT][FONT="]read_expire: In all 3 schedulers, there is some form of deadline to service each Read Request. The focus is read latencies. When a read request first enters the io scheduler, it is assigned a deadline that is the current time + the read_expire value in units of milliseconds. The default value is 500 ms.
write_expire: Similar to Read_Expire, this applies only to the Write Requests. The default value is 5000 ms.[/FONT][FONT="]
writes_starved: Typically more attention is given to the Read requests over write requests. But this can’t go on forever. So after the expiry of this value, some of the pending write requests get the same priority as the Reads. Default value is 1.
This tunable controls how many read batches can be processed before processing a single write batch. The higher this is set, the more preference is given to reads.
CFQ
back_seek_max: The scheduler tries to guess that the next request for access requires going backwards from current position on the Disc. Given that such going back can be time consuming. So in anticipation, may move back on the disc prior to the next request. This setting, given in Kb, determines the max distance to go back. Default value is set to 16 Kb.
Do note that in a cellphone or tablet, the storage is actually Flash Memory technology. There is Disk head to be re-positioned. As such this is not that effective as backward reads are not that bad.
[/FONT][FONT="]back_seek_penalty: This parameter is used to compute the cost of backward seeking. If the backward distance of a request is just 1 from a front request, then the seeking cost of the two requests is considered equivalent and the scheduler will not bias toward one or the other. This parameter defaults to 2 so if the distance is only 1/2 of the forward distance, CFQ will consider the backward request to be close enough to the current head location to be “close”. Therefore it will consider it as a forward request.
fifo_expire_async & fifo_expire_sync : This particular parameter is used to set the timeout of asynchronous requests. CFQ maintains a fifo (first-in, first-out) list to manage timeout requests. The default value is 250 ms. A smaller value means the timeout is considered much more quickly than a larger value. Similarly, fifo_expire_sync applies to the Synchronous requests. The default is 125 ms.
[/FONT][FONT="]group_idle: If this is set, CFQ will idle before executing the last process issuing I/O in a cgroup. This should be set to 1 along with using proportional weight I/O cgroups and setting slice_idle to 0 as Flash memory is a fast storage mechanism.
group_isolation: If set (to 1), there is a stronger isolation between groups at the expense of throughput. If disabled, Scheduler is biased towards sequential requests. When enabled group isolation provides balance for both sequential and random workloads. The default value is 0 (disabled). [/FONT][FONT="]
low_latency: When set (to 1), CFQ attempts to build a backlog of write requests. It will give a maximum wait time of 300 ms for each process issuing I/O on a device. This offers fairness over throughput. When disabled (set to 0), it will ignore target latency, allowing each process in the system to get a full time slice. This is enabled by default.
[/FONT][FONT="]Quantum: This option controls the maximum number of requests being processed at a time. The default value is 8. Increasing the value can improve performance; the latency of some I/O may be increased due to more requests being buffered inside the storage.
[/FONT][FONT="]slice_async: This parameter controls Maximum number of asynchronous requests at a time. The default value is set to 40 ms.[/FONT][FONT="]
slice_idle: When a task has no more requests to submit in its time slice, the scheduler waits for a while before scheduling the next thread to improve locality. The default value is 0 indicating no idling. However, a zero value increases the overall number of seeks. Hence a Non-zero number may be beneficial.
slice_sync: This setting determines the time slice allotted to a process I/O. The default is 100 ms.
BFQ
timeout_sync & timeout_async: These parameters determine maximum disk time given to a task, respectively for synchronous and asynchronous queues. It allows the user to control the latencies imposed by the scheduler.
[/FONT][FONT="]max_budget: This determines, how much of the queue request is serviced based on number of sectors on disc. A larger value increases the throughput for the single tasks and for the system, in proportion to the percentage of sequential requests issued. Consequence is increasing the maximum latency a request may incur in. The default value is 0, which enables auto-tuning
[/FONT][FONT="]max_budget_async_rq: This setting determines number of async queues served for a maximum number of requests, before selecting a new queue.[/FONT][FONT="]
low_latency: When this is set to 1 (default is 1), interactive and soft real-time applications experience a lower latency.
Row:
[/FONT][FONT="]hp_read_quantum: Dispatch quantum for the high priority READ queue
rp_read_quantum: Dispatch quantum for the regular priority READ queue
hp_swrite_quantum: Dispatch quantum for the high priority Synchronous WRITE queue
rp_swrite_quantum: Dispatch quantum for the regular priority Synchronous WRITE queue
rp_write_quantum: Dispatch quantum for the regular priority WRITE queue
lp_read_quantum: Dispatch quantum for the low priority READ queue
lp_swrite_quantum: Dispatch quantum for the low priority Synchronous WRITE queue
read_idle: Determines length of idle on read queue in Msec (in case idling is enabled on that queue).
read_idle_freq: Determines the frequency of inserting READ requests that will trigger idling. This is the time in Msec between inserting two READ requests[/FONT]
5. CPU GOVERNORS –
THIS SECTION IS STILL IN PROGRESS. I WILL KEEP UPDATING.KINDLY BEAR WITH ME.
References -
http://androidforums.com/xperia-mini-all-things-root/513426-android-cpu-governors-explained.html
http://forum.xda-developers.com/showpost.php?p=28647926&postcount=1
http://pic.dhe.ibm.com/infocenter/l...ic=/liaai.cpufreq/TheConservativeGovernor.htm
http://lists.linaro.org/pipermail/linaro-kernel/2012-February/001120.html
A Governor performs a similar function for the CPU time management as the Scheduler. Originally, there were a set of Governors coming from the Linux kernel. Over the period, newer governors were introduced for Android architecture. Several developers added their own governors by modifying or tweaking existing governors.
To fully utilize the governors, you need to disable a file called mpdecision. It's located under /system/bin. It interferes with the governors operation and won't allow you to take full advantage of it's settings. Typically you can do this by renaming the file name using ES File Explorer and rebooting the phone. Note that if you use the Touchwiz JELLYBEAN version, you should rename /system/bin/qosmgr to /system/bin/qosmgr.bak .
Essentially with either file, governor’s instructions for the second CPU are overridden. By renaming them, they are not loaded at Boot. So governor’s authority is restored.
ONDEMAND -
Reference - http://pic.dhe.ibm.com/infocenter/l...ic=/liaai.cpufreq/TheConservativeGovernor.htm
The ondemand governor dynamically changes CPU frequency in response to CPU utilization. It will automatically select the highest available processor frequency when the processor load rises above value set by up_threshold. If CPU utilization rises above the up_threshold parameter, the ondemand governor increases the CPU frequency to scaling_max_freq. When CPU utilization falls below this threshold, the governor decreases the frequency in steps to run at the next lowest frequency until it reaches scaling_min_freq. After each sampling_rate milliseconds, the current CPU utilization is reexamined and the process is repeated dynamically to adjust the CPU frequency per process load. Since the governor needs time to respond, performance might be reduced if the usage changes frequently.
CONSERVATIVE –
Reference- http://pic.dhe.ibm.com/infocenter/lnxinfo/v3r0m0/topic/liaai.cpufreq/TheConservativeGovernor.htm
This governer prefers the lowest possible clock speed as often as possible. Only upon a larger persistent load on the CPU will the conservative governor raise the CPU clockspeed.
This will tend to try and keep the CPU running at lower speeds and consequently lower voltage. This inherently will conserve the battery.
Like the Ondemand governor, it steps the CPU through the operating frequencies by dynamically adjusting frequencies based on processor utilization. However, the conservative governor increases and decreases CPU speed more gradually as against the hair trigger response of OnDemand governer. This governor increases the frequency step by step upon CPU load but jumps to lowest frequency when the CPU load is removed. Thus it aims to dynamically adjust the CPU frequency to current utilization, without jumping to max frequency. If CPU utilization is above up_threshold, this governor will step up the frequency to the next highest frequency below or equal to scaling_max_freq. If CPU utilization is below down_threshold, this governor will step down the frequency to the next lowest frequency until it reaches scaling_min_freq. After each sampling_rate milliseconds, the current CPU utilization will be reexamined and the same algorithm will be applied to dynamically adjust the CPU frequency to current utilization.
Note - Depending on how the developer has implemented this governor, and the minimum clockspeed chosen by the user, you may experience some choppiness or random freeze. So you need to choose its settings more judiciously.
KTOONSERVATIVE –
As I said earlier, Ktoonservative is a Hotplug derivative of the traditional Conservative Governor. Hot plugging allows the governor to turn off second core of the processor dynamically. This maintains a healthy balance of Performance and Battery life.
I wish to respectfully quote @freecharlesmanson.
Ondemand scales to the highest frequency as soon as a load occurs. Conservative scales upward based on the frequency step variable which means for the most part will scale through every frequency to achieve the target load thresholds. What this practically means is ondemand is prone to wasting power on unneeded clock cycles. Ondemand also features something called a down differential, this variable determines how long the governor will remain at the given frequency before scaling down. Conservative does not have this, but instead relies on having a down threshold which insures that as soon as the load drops below a given variable it scales down as fast as the sampling rate allows. The result to this is a governor which attempts to keep the load level tolerable and save you battery! Now ! Ktoonservative Is that but in addition contains a hotpluging variable which determines when the second core comes online. The governor shuts the core off when it drops below the hotplug down threshold thus giving us a handle on the second performance factor in our CPUs behavior. While by default conservative is a poor performer it can be made to perform comparably to even performance governor. Here are some settings to discuss and start with. They are slightly less battery friendly under a load but very very well performing.
Click to expand...
Click to collapse
SMARTASSH3 –
This is a balanced governor that tries to balance between Performance and Battery life. This governor is based on the SmartassV2 Governor. Since it was tweaked by H3ROS, the name is modified. The V2 in turn is a derivative of the original SmartAss governor. It tries to attain an Ideal frequency by ramping up to that frequency quickly. Once reached, further ramping is done very slowly. This Ideal value is user defined in the Governor settings.
The governor also has different frequencies for Screen ON and Screen OFF states along with Sleep state.
NIGHTMARE -
This is one of the newer Performance oriented governor. It tries to reach the top frequency by scaling rapidly. Once reached, it tries to maintain the frequency as much as possible. It is based on the PegasusQ governor.
It is multi-core version of the Ondemand governor with integrated hot-plugging. Ongoing processes in the queue can run simultaneously . These processes are in a “Run Queue" queue that is ongoing. The processes are arranged according to their priority values. To ensure that each process has its fair share of resources, each is run for a certain period and then stops and placed in the queue for next turn. This continues until the processes are terminated.
DANCEDANCE –
This governor is based on the Conservative Governor. It was created by Snuzzo by modifying Ramp up rate to be higher as well as Sleep routines.
WHEATLEY –
This one took some digging as Wheatley is not a Linux Governer brought to Android. XDA Developer @phone_user implented this governer for his Samsung Galaxy Nexus Kernel.
In essence, this governer takes on a novel approach to power saving. As you may deduced so far, making the CPU operate at lowest needed frequency (like conservative does), can potentially backfire with CPU taking more time (and more consumption over time) to finish the task. So Wheatley actually targets the CPU Frequencies and its Deep Sleep State (AKA C4 State). In this state, the CPU voltage is reduced to avoid unnecessary power consumption.
So respectfully quoting him for the details.
phone_user said:
The previous benchmarks of the usage of the C4 state for different activities have shown that for 'light' tasks like browsing the internet, reading (for example emails or eBooks) and the average app the device spends about 40% of the time in C4 with acceptable average residencies of around 11ms. For more demanding tasks like games and video playback the C4 state is still being used however the efficiency is reduced due to the low average residencies of below 5ms (considering that the wakeup latency is 1.3ms).
I have run a few tests and as it turns out, for demanding tasks the efficiency of the C4 state is significantly reduced due to these low residency times (= large number of wakeups) to a point that the good old frequency scaling is indeed more efficient with larger battery savings. So unfortunately, relying on the C4 state alone for power savings for all tasks is not a good option.
However, unfortunately we also cannot simply use one the available standard governors since always try the minimize the frequency without taking account that this behaviour diminishes the efficiency of the C4 state since it hinders a proper race-to-idle. So taking advantage of this knowledge what a good governor should do, is using the maximum frequency whenever the C4 state is properly used with acceptable average residencies and only scale down when the average residencies get too low (or the C4 is not used at all, of course).
Building on the classic 'ondemand' governor I implemented this idea in my new Wheatley governor. For internet browsing the time spend in C4 has increased by 10% points and the average residency has increased by about 1ms. I guess these differences are mostly due to the different browsing behaviour (I spend the last time more multi-tabbing). But at least we can say that Wheatley does not interfere with the proper use of the C4 state during 'light' tasks. For music playback with screen off the time spend in C4 is practically unchanged, however the average residency is reduced from around 30ms to around 18ms, but this is still more than acceptable.
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.
Click to expand...
Click to collapse
ABYSSPLUG –
This is a Modifed version of the Hot Plug Governer. It is similar to the On Demand governor, but is more accurate steps through CPU frequencies depending on CPU load. Like the Hotplug governor, it turns off unused CPU cores upon low CPU utilization.
BADASS –
ASSWAX –
SlP –
PEGASUSQ –
ADAPTIVE –
INTERACTIVE –
This governor is designed for latency-sensitive workloads, such as interactive user apps. The interactive governor aims to be significantly more responsive to ramp CPU quickly up when CPU-intensive activity begins.
Existing governors sample CPU load at a particular rate, typically every X ms. This can lead to lag from the time user begins interacting with a previously-idle system until the next sample period.
The Interactive governor, instead of sampling the CPU Load, it will check whether to scale up CPU frequency immediately after CPU becomes active. This is done with a timer, that triggers within 1-2 ticks. If the CPU is very busy after becoming active, then the governer assumes the CPU to be underpowered and will ramp to MAX speed. If the CPU was not sufficiently busy to immediately ramp to MAX speed.
After this, the governor evaluates CPU load, choosing the highest value between longer-term load or the short-term load since idle exit to determine the CPU speed to ramp to.
A realtime thread is used for scaling up, giving the remaining tasks the CPU performance benefit. This is unlike existing governors which are more likely to schedule other tasks to occur after your performance starved tasks have completed.
USERSPACE -
This governer allows for more granular control over Power policy for the device. It allows any user apps to set the processor frequency. It does not dynamically change the CPU frequency or react to processor load, rather it only provides a mechanism to set the frequency through the use of the scaling_speed parameter. However, KT747, does not implement any tunable parameters for the user.
POWERSAVE -
As the name says, the only priority for this governer is to provide power saving with no regard for apps being slowed down. This can be counter intuitive since slowed down apps will take even longer time and thus drain battery further.
It sets the CPU to the value of the scaling_min_freq parameter. (Default value is the lowest available processor frequency). However, KT747 does not offer this parameter as a tunable within the KTweaker application.
PERFORMANCE -
As the name says, this governor exclusively focuses on providing consistent minimum latency. This governor sets the CPU speed to the highest available frequency. The CPU speed is always set to the frequency defined in scaling_max_freq parameter. (Default is the highest available processor frequency). However KT747 does not expose this setting via the KTweaker application.
6. CPU GOVERNOR ADJUSTMENTS
Governor Adjustments are typically parameters for a given governor that you can further tweak. There are certain Performance Scripts out there that may set some of these parameters as well. One such example is System Performance Mod Thunderbolt! By @pikachu01
Given below are some of the parameters of commonly used Governors. There are quite a lot of parameters for each governor. Having to list each one will be pretty intensive. I may choose to add these in future as time permits AND if there is a demand for it. In addition, I am adding Hide tags for each governor in order to tidy up the post.
ONDEMAND GOVERNER-
Ignore_nice_load - You can use the ignore_nice_load option to ignore all processes, that run with a positive nice value. These will not be counted toward the overall CPU utilization. Set this parameter to 1 if you do not care how long it takes for such processes to complete.
sampling_rate - Measured in us. , this is how often the kernel look at the CPU usage and make decisions on what to do about the frequency. Higher values means CPU polls less often. For lower frequencies, this could be considered an advantage since it might not jump to next frequency very often, but for higher frequencies, the scale-down time will be increased.
up_threshold - Measured in percentage 1-100, When CPU load reaches this point, governor will scale CPU up. Higher value means less responsiveness and lower values corresponds to more responsiveness at the cost of battery.
powersave_bias - Default value is 0. Setting a higher value will bias the governor towards lower frequency steps. Use this if you want CPU to spend less time on higher frequencies. A better alternative would be to underclock to a lower frequency than using powersave bias.
The powersave_bias parameter modifies the behavior of the ondemand governor to save more power by reducing the target frequency by a specified percentage. By default, the it selects the minimum processor frequency that can still complete a workload with minimal idle time. Doing so should result in the highest performance to power efficiency ratio. In some cases, you might prefer a greater emphasis on power efficiency than performance. In this case, set the powersave_bias parameter to a value between 1 and 1000 to reduce the target frequency by one-thousandth of that value. Say if you set powersave_bias to 100 it will cause a one-tenth reduction in target frequency. If the Max frequency of the device is 2 GHz, the governor instead will request 1.8GHz – a one-tenth reduction. If 1.8 GHz is an exact match with an available hardware frequency (listed in the scaling_available_freq parameter), the processor is set to this frequency. If 1.8 GHz is not available, the processor fluctuates between the closest available upper and lower frequencies for an average frequency of 1.8 GHz. The default value is 0.
sampling_down_factor - In the simplest form, sampling_down_factor determines how often CPU should stay at higher frequencies when truly busy. Default behavior is fast switching to lower frequencies (1). Having sampling_down_factor set to 1 makes no changes from existing behavior (for the non-modified ondemand), but having sampling_down_factor set to a value greater than 1 causes it to act as a multiplier for the scheduling interval for re-evaluating the load when the CPU is at its highest clock frequency (which is scaling_max_freq) due to high load. This improves performance by reducing the overhead of load evaluation and helping the CPU stay at its highest clock frequency when it is truly busy, rather than shifting back and forth in speed. This tunable has no effect on behavior at lower frequencies/lower CPU loads.
down_differential - This factor indirectly calculate the 'down-threshold' of Ondemand. After completing sampling-down-factor*sampling-rate at max frequency because of high load, governor samples the load again to calculate an estimate of the new target frequency in a way that the lowest frequency will be chosen that would not trigger up_threshold in the next sample. Because triggering up-threshold will again cause CPU to scale up to max frequency. During this choice down_differential is taken into account as a breathing room value. Target frequency is calculated as max_load_freq / (up_threshold - down_differential). The obtained value might be a non-existent value in the freq_table and CPU driver will round it off to a value in freq_table. max_load_freq is the theoretical frequency at which CPU can handle 100% workload. It is usually a value below scaling_max_freq. See this post by AndereiLux for more info.
freq_step - Whenever up-scaling logic is triggered the governor instructs the CPU to raise its frequency by freq_step percentage of max allowed frequency. (max policy * (freq step / 100)). Ex: max policy is 1600 and freq step 21%, it will scale 1600 * 21% = 336. We have a 100MHz grained frequency table so it rounds up to the next 100MHz, hence 336 becomes 400. So say we're idling at 200MHz and the up-scaling logic gets triggered with the above settings, the next frequency will be 600MHz. Note that freq_step and smooth_scaling does pretty much the same thing.
SMARTASSV2 GOVERNER –
awake_ideal_freq - The frequency until which CPU is scaled up rapidly on screen-awake (from sleep). Thereafter, scaling up is less aggressive.
sleep_ideal_freq - The frequency until which CPU is scaled down rapidly when screen is turned off. Thereafter, scaling down is less aggressive.
up_rate_us - The minimum amount of time to spend at a frequency before we can ramp up. (Ignored below awake-ideal frequency since governor needs to rapidly scale up to awake_ideal_freq when below it)
down_rate_us - The minimum amount of time to spend at a frequency before we can ramp down. (Ignored above sleep-ideal frequency since governor needs to rapidly scale down to sleep_ideal_freq when above it)
max_cpu_load - Same as up_threshold in other governors.
min_cpu_load - Same as down_threshold in other governors.
ramp_down_step - Frequency delta when ramping down below the ideal frequency. Zero disables and will calculate ramp down according to load heuristic. When above the ideal frequency we always ramp down to the ideal freq.
ramp_up_step - Frequency when ramping up above the ideal frequency. Zero disables and causes to always jump straight to max frequency. When below the ideal frequency we always ramp up to the ideal freq.
sleep_wakeup_freq - The frequency to set when waking up from sleep. When sleep_ideal_freq=0 this will have no effect.
KTOONSERVATIVE & CONSERVATIVE GOVERNER-
Boost_2nd_Core_On_Button -
This configuration option when set, allows you to turn the second Core ON with Back+Home+Menu button combo.
Boost_CPU - @KToonsez hasn't documented much on this setting. But based on my experiments, I feel that this, specifies the frequency to which the second Core is set when turned on by the button combo above.
Boost_GPU - Similar to Boost_CPU, this will set the frequency of operation of the GPU when the second core is turned on.
Boost_Hold_Cycles -
This setting specifies the duration for which the Core 2 will be kept on. A value of 22 translates as 1 second.
Boost_Turn_on_2nd_Core -
When set, this setting will make second core turn on immediately on touch.
CPU_Down_Block_Cycles -
This setting is used to counteract the effects of hot plugging. It specifies duration for which the CPU Cycles are throttled before hot plugging the second core out.
Disable_Hotplug_BT -
As the name suggests, when set. this setting will stop the second core from being turned off when Bluetooth connection is active.
Disable_Hotplugging -
When set the entire process of hot plugging is turned off.
freq_step - Defines how much (as a percentage of the maximum CPU speed) the conservative governor will increase the CPU speed by each time the CPU load reaches the Up Threshold.
sampling_down_factor & sampling_rate- The sampling_down_factor value acts as a negative multiplier of sampling_rate to reduce the frequency that the scheduler samples the CPU utilization. For example, if you set sampling_rate to 10,000 and sampling_down_factor to 2, the scheduler samples the CPU utilization every 20,000 microseconds.
freq_step - The freq_step parameter changes the size of the frequency step that the governor uses to change CPU frequency in either direction. By default this setting is 5, which means the governor will change the CPU frequency by five percent of the maximum or minimum frequency each time it changes frequencies. If you set this value to 100, the governor will behave exactly like the ondemand governor and immediately increase to the highest speed.
ignore_nice_load - You can set the ignore_nice_load option to ignore all processes that run with a positive nice value will not be counted toward the overall CPU utilization. Hence will not cause the CPU frequency to increase and might take longer to complete. When set to 0 (the default), all processes are counted toward the CPU utilization value. When set to 1, niced processes are ignored.
No_2nd_CPU_Screen_Off -
As the name says, setting this to 1 (default value), will turn off second core on your device. For those with more than 2 cores, there will be corresponding settings for 3rd and 4th core.
Sampling_Down_Factor - This parameter controls the rate at which the
kernel makes a decision on when to decrease the frequency while running
at top speed. When set to 1, decisions to re-evaluate the CPU load, are made at the same interval regardless of current clock speed. But when set to greater than 1 (e.g. 2 Default value) it acts as a multiplier for the scheduling interval for reevaluating load when the CPU is at its top speed due to high load.
This improves performance by reducing the overhead of load evaluation and helping the CPU stay at its top speed when truly busy, rather than shifting back and forth in speed. This tunable has no effect on behavior at lower speeds/lower CPU loads.
Sampling_Rate - This is measured in uS (10^-6 seconds). That is how often the kernel will poll the CPU usage and make decisions on what to do about the frequency. It's default value is 25000.
Sampling_Rate_Min - As the name states, this value provides a minimum limit on the Sampling_Rate. This is based on the Hardware Latency and Kernel variables. Default value is 10000.
Sampling_Rate_Screen_Off - As the name suggests, this is the value of Sampling_Rate when the screen is turned off. Default Value 40000.
Up_Threshold - It specifies what the average CPU usage between the samplings of 'sampling_rate' needs to be for the kernel to determine if it should increase the frequency. For example when it is set to '70', between the checking intervals the CPU needs to be average more than 70% in order to determine that the CPU frequency needs to be increased.
Up_threashold_Hotplug - As the name suggests, this value determines when to bring the second Core Online. It is done when the CPU load reached this %.
INTERACTIVE GOVERNER-
hispeed_freq - An intermediate "hi speed" at which to initially ramp when CPU load hits the value specified in go_hispeed_load. If load stays high for the amount of time specified in above_hispeed_delay, then speed may be bumped higher. Default is maximum speed.
Above_hispeed_delay - Once speed is set to hispeed_freq, wait for this long before bumping speed higher in response to continued high load. Default is 20000 uS.
go_hispeed_load - Go to hi speed when CPU load at or above this value. (Similar to Up-Threshold in other governors). The CPU load at which to ramp to the intermediate "hi speed". Default is 85%.
min_sample_time - The minimum amount of time to spend at the current frequency before ramping down. This is to ensure that the governor has seen enough historic cpu load data to determine the appropriate workload. Default is 80000 uS.
timer_rate - The sample rate of the timer used to increase frequency. It reevaluates cpu load when the system is not idle. Default is 20000 uS.
input_boost: If non-zero, boost speed of all CPUs to hispeed_freq on touchscreen activity. Default is 0.
boost: If non-zero, immediately boost speed of all CPUs to at least hispeed_freq until zero is written to this attribute. If zero, allow CPU speeds to drop below hispeed_freq according to load as usual.
boostpulse: Immediately boost speed of all CPUs to hispeed_freq for min_sample_time, after which speeds are allowed to drop below hispeed_freq according to load as usual.
WHEATLEY GOVERNER -
target_residency - The minimum average residency in µs which is considered acceptable for a proper efficient usage of the C4 state. Default is 10000 = 10ms.
allowed_misses - The number sampling intervals in a row the average residency is allowed to be lower than target_residency before the governor reduces the frequency. This ensures that the governor is not too aggressive in scaling down the frequency and reduces it just because some background process was temporarily causing a larger number of wakeups. The default is 5.
VOLTAGES SECTION –
This Section lists all the possible Operating Frequencies of the Processor of the phone. The Mili Volt (MV) define the operating power in Volts of the Processor at that frequency. Some basic facts for you to understand. The Frequencies determine how fast the Processor will be operating. The voltages determine Juice provided to the processor. As a processor consumes higher voltage, it will generate more heat. So this section is very important and critical to everyone who wishes to either Overclock or Undervolt. Overclocking is a term used to determine how the operating Frequencies are controlled in order to obtain maximum performance and fastest response time. As we saw in the General Section, the Enable Overclock checkbox allows you to push the boundaries of the operating frequencies. So the processor will offer better performance, but will also generate more heat due to higher operating voltages. So in this section you will need to cool down the processor by applying lower operating voltage. This however should not be confused with undervolting.
Undervolting is a concept that is used to obtain highest amount of Battery life. As the operating voltage is the major consumer of the battery, lowering operating voltages in steps of 25 will allow the processor to operate at that frequency with a possible Lag. Weather you do notice the lag or not is dependent on how much the voltage is lowered. It is also dependent on the Max & Min Operating frequencies you chose in the General Section.
Having said that, on this screen, you can press the menu button to get a new menu. This menu will allow you to modify voltages set at each frequency step.
The option to Load Stock table allows you to reset to Default voltage values in case you wish to revert. Rest of the options to add or Subtract will let you change all steps in bulk. So for ex. the option to add 5 Volts to all steps will add 5 mv to current voltage for that step. The settings option does not seem to do anything.
[FONT="]NOTE – Even though the options are in VOLTS, they should read Milli Volts.[/FONT]
EXTRAS -
Eventhough this is called EXTRA, it actually has quite a few important options. Chief among these, is the ability to set different Governors under certain circumstances as well as setting a different upper limit on frequency.
SCREEN OFF PROFILE Mhz –
As the name says, this determines the upper limit on Operating Frequency when the Screen is Off. Thus it will override what you set on General screen. This is good to have if you want the frequency further throttled when you are not using or just have different frequency for background apps when not using.
NOTE – If you set screen turn off time too low, and the screen turns off when you are reading something; you will have unexpected consequences. Not to mention battery or smoothness hit.
DISABLE SCREEN OFF Mhz CALL –
This is a further addition to the Screen off Profile discussed above. When set, this option will apply the Screen Off Profile when you are on a call. Thus applying the frequency you set in the previous option. So you need to do this carefully in order not to get your phone unresponsive or FC’d in the middle of a call.
SCREEN OFF PROFILE GOV. –
As the name says, you get to set a different governer when screen is off. This will override what you chose in the governer choice. Pretty nifty arrangement so that you can flip from a performance governer when on screen and a power save governer when screen is off. Keep in mind the time out screen off when you are reading without interacting.
SCREEN OFF PROFILE SCHED –
Similar to the Governer, this will let you choose a different Scheduler for when the screen is off. This will override (when screen is off) what you set previously.
GPS PROFILE GOV –
Similar to Screen off, this will set a Governer choice that comes into play when you are navigating or have the GPS on. If, some of you tend to keep the GPS on permanently then keep in mind that your main choice of governer will be permanently overridden.
GPS PROFILE SCHED –
Similar to the Governer, you get to choose which Scheduler comes into play when you are navigating. Keep in mind that, during navigation, the phone will keep reading from the Google Map Cache or any other Navigation product you may be using. So choose Scheduler appropriately.
BLUETOOTH PROFILE MHZ –
This setting determines the MINIMUM operating frequency when the phone is paired over Bluetooth to another device. This is unlike the Screen off option where the Max frequency is determined.
FAST CHARGING –
One of the coolest feature of the Kernel. When set, the phone will charge off of the PC USB ports as if it is connected to wall outlet. This does turn off your access to the phone internal memory and SD card. If you want to access the internal storage on PC then you have to turn this off.
NOTE – Weather to turn on or off, has to be done before connecting to PC. Changing this after connecting has no effect.
VIBRATION STRENGTH –
This Kernel parameter is actually a multiplier. It actually determines the intensity of vibration when the phone is in vibrate mode or ring Plus Vibrate Mode. It also determines vibrations of the notifications you receive. (It is possible it also determines In-App or In-Game vibrations. I did not test). It’s a good thing to control as some of the roms have very low vibration intensity out of box. Do note that vibrations do chew up your battery. So don’t set it too high. Based on my experiments, the out of box setting at 120 seems good enough.
SWIPE 2 WAKE –
This is an Interesting concept. If this is set, then you get to short circuit the process of waking the phone. What you need to do is slide through the capacitive buttons on your phone as if you are sliding the screen to unlock. This bypasses the step where you press power or home button to wake to lock screen and then actually unlock the phone.
Given that my phone SGH-T999 does not have all Capacitive buttons, it does not seem to work. Besides I have secured pin on my lock screen so it won’t unlock by this method either. (I don’t find it that useful either.)
INTERNAL READ AHEAD, EXTERNAL READ AHEAD –
Both of these parameters control the size of the buffer. Internal refers to your Internal SD Card & External refers to the MicroSD card. Do note, the buffer resides in RAM. So if you set it too high then you won’t have free RAM to play with. Also This must be used with a judicious choice of the Scheduler.
GPU GOVERNER –
This is probably of interest only to the gamers or Graphic intensive app users. Similar to the previous governer choices for CPU, this option allows you to further tweak the Governer choice for your GPU. It only affects the Graphics displayed. So unless you have graphic intensive app running, you won’t notice the difference. By default it will use the Governer set for the CPU.
TRINITY COLORS –
This of this, like the Gamma control on your TV or a monitor. This determines the basic color pallet on your phone. Think of it as if you applied a color filter to the screen. Based on what value you set here, effect will be immediate.
CONGESTION CONTROL –
First of the TCP/IP network performance parameter. TCP Congestion Control determines which algorithm is applied for the network congestion avoidance. You have two choices. Cubic & Reno. Cubic is less aggressive and Reno is more aggressive. Suffice it to say that pretty much every one will have their own performance. So there is no recommendation. For the more geeky minded, here’s the Wikipedia link.
TIME WAIT RECYCLE –
Second of the TCP/IP network performance parameter. This parameter determines, how long will the system wait before it will recycle a connection in wait state. It will benefit those on Wireless or high speed data plans. Default is Enabled. So if you have perennial bad performance on high speed connection, you can turn it off.
TIME WAIT REUSE –
Third of the TCP/IP network performance parameter. Similar to Recycle above, this too controls the time before the system reuses a connection. This too is set to Enable. Turn it off if you have connectivity issues.
SHOW TOAST MESSAGES –
This controls weather Kernel response messages are displayed on screen. These are either for the automated actions or response to changes you made. Default is enabled.
ENABLE KTWIDGET TIMER –
To be honest, I have no idea what this does. If someone is willing to share, I will be more than happy to add.
BATTERY MHZ CONTROL –
This actually has its own sub menu. Effectively it allows you to throttle down the CPU frequency if the battery is too low or is high. You also get to define what is the low level and what is the high level. Lastly, you can turn it off while charging.
NOTE – This has a direct conflict with what frequencies you have set on the main screen. So use judiciously.
KTHERMAL CONTROL –
This too has its own sub menu with several options. Effectively it allows you to throttle down the CPU and GPU in case the phone has heated, as the warning correctly says on the submenu, if you don’t set it correctly, you will damage the processor.
The options are pretty much self explanatory. Just to keep the noobs from killing their phones, I am not explaining each option. If there is high demand, I will add individual description here.
GET LAST_KMSG, GENERATE A DMESG, GENERATE A LOGCAT –
[FONT="]All three of these are KTOONSEZ’s way of grabbing error messages in case stuff happens. These are saved as text files on your internal sd card. You will only need these options if you are trying to identify a possible kernel issue.[/FONT]
SET OPTIONS ON BOOT -
This option allows you to choose when to apply the settings you have provided here. You may apply them immediately after booting or wait for some time before applying. If you are testing some exotic setting, choose to apply with delay so that you have time to revert to stock.
BACKUP PREFS TO SDCARD –
Pretty much self explanatory. It exports the settings to internal SD Card under the path you specify.
RESTORE PREFS FROM SDCARD –
Same as above, allows you to restore settings previously exported.
LOAD DEFAULTS –
Allows you to set default values of the kernel. These are the values, KTOONSEZ has set for the kernel. Safe spot to run to if you managed to mess up the settings.
That pretty much concludes all the options on the KTweaker app.
RECOMMENDED SETTINGS -
This section is intended to provide basic stable profiles that have been tested repeatedly. These profiles would help beginners to get started in the direction they wish to go. Of course they may not be the best in that class. But then no two phones are same so what works for one may not work for others.
Note-
For those who wish to further Battery life, you may do well to visit this thread on Eliminating Google Services Wakelock.
The general process for using these files is as follows.
1. Download the file(s) to your phone. In case of .BIN files, optionally rename as .TXT
2. Copy the file(s) to /SDCARD/KTweaker folder with file Manager of your choice.
3. Open Ktweaker app, click on Import Settings.
4. The file you just copied should be listed there.Choose the one you want to apply.
5. After applying, make sure Set Options on Boot Setting on main Menu of the KTweaker app has a little green text bellow confirming that the settings will be applied upon reboot.
6. Profit !
If you are hungry for more or wish to tinker further, head over to the Team Kernerlizer Threads. Links are given bellow. (Hidden in order to tidy up the thread.)[/COLOR]
Team Kernalizer Galaxy SIII threads by Carrier -
Team Kernalizer Thread for T Mobile Galaxy SIII / D2TMO - Thread Link
Team Kernalizer Thread for Sprint Galaxy SIII / D2SPR - Thread Link
Team Kernalizer Thread for AT&T Galaxy SIII / D2ATT - Thread Link
Team Kernalizer Thread for Verizon Galaxy SIII / D2VZW - Thread Link
Given bellow are some of the tried and tested profiles.
1. Conservative Battery Saver Profile -
Conservative Balanced Settings by @LuigiBull23
Settings File is for AOSP version of the Kernel. Attached to this post - ROW-Balanced_Bull_v2.txt
The battery life for him with these settings can be seen bellow.
I on the other hand had a little bit better luck with my light to moderate use. (Hidden to tidy up the thread).
NOTE - I had accidentally connected the phone to Laptop for a minute or 2 when Battery was at 12 % (Fast Charge was ON).
Do Please note, there is an additional experimental profile called Bless the Child V3 by @LuigiBull23 that Ihave attached bellow. Try if you wish. I will post the results of my test after next Charge Cycle.
LuigiBull23 said:
ROW Balanced Bull v3
***Reported to have resolved issues with battery drain, overheating, and random reboots!***
General
Locked Frequencies
CPU (MIN): 135Mhz
CPU (MAX): 1404Mhz
Scheduler: ROW
Scheduler Adjustments:
> hp_swrite_quantum = 3
> low_starv_limit = 8000
> rd_idle_data = 5
> rd_idle_data_freq = 15
> reg_starv_limit = 4000
> rp_swrite_quantum = 2
> rp_write_quantum = 2
Governor: Ktoonservative
Governor Adjustments:
> boost_cpu = 1026
> boost_hold_cycles = 18
> boost_turn_on_2nd_core = 0
> down_threshold = 58
> down_threshold_hotplug = 65
> freq_step = 2
> sampling_down_factor = 2
> sampling_rate = 25000
> sampling_rate_screen_off = 40000
> up_threshold = 70
> up_threshold_hotplug = 80
Voltages
CPU: -30mV across the board
GPU: -50mV across the board
Extras
Screen Off Profile Mhz: 378
Screen Off Profile Gov: Same as selected governor
Screen Off Profile Sched: Same as selected scheduler
Miscellaneous Section:
> Vibration Strength: 60
SD Card Section:
> Internal Read Ahead = 2048
> External Read Ahead = 2048
Battery Mhz Control:
> Battery Level Low: 20
> CPU Mhz for Low Level Battery: 1080Mhz
[/CODE]
Click to expand...
Click to collapse
2. Extreme UNDERVOLTING PROFILE -
Extreme Undervolting without Lag by @iamikon
iamikon said:
Forget that try this! SIO-NoCleverName-AOSP
http://db.tt/3dcMQCz0
Click to expand...
Click to collapse
NOTE - You may need to up voltage by 50 mV if you continue to experience lag or Freeze.
Settings File for AOSP Version of the Kernel is attached - sionoclevernameaosp.txt
3. Gamer (Or Game intensive) PROFILE -
Thanks to @RErick, here's a good stable setup for those who wish to play Graphic Intensive (Shadowgun DeadZone ) games on their phones.
Obviously, you won't be expecting outstanding battery life with intense gaming. (Can I get Prius Gas Mileage from a Corvette ?) But if you do, @RErick has graced us with this Profile. Do note this second profile may potentially lag under heavy Graphics.
But
@Perseus71
http://lwn.net/Articles/509829/
Info on ROW scheduler
castle_bravo said:
@Perseus71
http://lwn.net/Articles/509829/
Info on ROW scheduler
Click to expand...
Click to collapse
Thanks Castle. Appreciate the link.
It's about damn time!! lol I've been waiting for a guide like this that works in correlation to the Ktweaker app.. It will definitely benefit to newcomers as well as current users of this kernel.
Great guide! Thanks buddy :good:
Great guide, excellent work! Subscribed!
Great work my friend will be adding this to all the tk threads if you ever need anything just give a buzz we would glad to help anyway possible and again great write up amd guilde very informative
http://pbr1202.photobucket.com/albums/bb374/TexasEpic/Requested Banners/SPH-L720v3_zps61b75aad.png
Look good friend. Keep up the good work. I will link in my threads too
Hi nice work there, but is there any latest settings for tw version ? Or have i missed it ?
Rayfucious said:
Hi nice work there, but is there any latest settings for tw version ? Or have i missed it ?
Click to expand...
Click to collapse
I personally use AOSP Roms. So I can't translate them to Touchwiz. However, I have given the individual setting Values for the Balanced Profile. You can enter these values into KTweaker to get the file.
Perseus71 said:
I personally use AOSP Roms. So I can't translate them to Touchwiz. However, I have given the individual setting Values for the Balanced Profile. You can enter these values into KTweaker to get the file.
Click to expand...
Click to collapse
So i can enter the above values into TW version and compatible ? cause i thought aosp kernel settings and tw would be different.
Can't find this 2 settings in ktweaker for tw version though.
up_threshold_hotplug = 80
down_threshold_hotplug = 62
The rest are fine though. Will be trying out and see how it goes.
Is there an oreo-based kernel to perform cpu underclocking? Or maybe a way to be able to do the underclock on android 8? Because most of them are only on android nougat, but on oreo no one has developed anything yet ...
AntoKemz said:
Is there an oreo-based kernel to perform cpu underclocking? Or maybe a way to be able to do the underclock on android 8? Because most of them are only on android nougat, but on oreo no one has developed anything yet ...
Click to expand...
Click to collapse
There is an app I used on my old phone: https://play.google.com/store/apps/details?id=com.grarak.kerneladiutor
Sent from my Samsung SM-A520W using XDA Labs
AntoKemz said:
Is there an oreo-based kernel to perform cpu underclocking? Or maybe a way to be able to do the underclock on android 8? Because most of them are only on android nougat, but on oreo no one has developed anything yet ...
Click to expand...
Click to collapse
You can underclock with stock kernel if I know correctly.
The stock oreo kernel of a520f supports these features and it should apply to (Exynos) most custom kernels, all devices across A 2017, and most related devices.
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq - Max clock of cluster 0, reduce to underclock the CPU.
/sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq - Max clock of cluster 1, reduce to underclock the CPU.
/sys/power/cpufreq_max_limit - Max clock of both clusters, more forced once permissions are set, watch device temperatures.
/sys/power/cpuhotplug/max_online_cpu - write a number 1 to 8, it is the CPU cores that are online.
Maybe relevant:
/sys/class/misc/mali0/device/dvfs_max_lock - GPU clock, more forced once permissions are set, watch device temperatures.
/sys/class/misc/mali0/device/core_mask - The GPU core combination in use, write a number 1 to 7.
/sys/class/misc/mali0/device/dvfs_governor - GPU governor, write a number 1 to 3.
/sys/class/devfreq/17000010.devfreq_mif/max_freq - could affect cellular and wifi
/sys/class/devfreq/17000020.devfreq_int/max_freq
/sys/class/devfreq/17000030.devfreq_disp/max_freq
/sys/class/devfreq/17000040.devfreq_cam/max_freq
The CPU governor is with scaling_max_freq though only userspace performance interactive.
Reboot to undo changes.
Edit:
/sys/devices/system/cpu/cpufreq/mp-cpufreq/cluster0_max_freq
/sys/devices/system/cpu/cpufreq/mp-cpufreq/cluster1_max_freq
Though this should not exceed the max clock, in addition to the governor's settings(/sys/devices/system/cpu/cpu[0-7]/cpufreq/interactive/...), the CPU clock is boosted temporarily when the screen is touched, the activity is changed, etc, even when it might not be needed. It's often "touchboost", and could be disabled by enabling medium power saving, or,
/sys/power/cpufreq_min_limit (home, gesture, scroll, app change, unlock)
"644 permissions" - disabled
"664 permissions" - default
check its contents after changing, should be the CPU min clock.
/sys/class/input_booster/level (touch, long touch, multiple fingers, etc)
0 - disabled touchboost
1 - low
2 - default
3 - high
might need the permissions being 464
CPU 4-7 needs to be powered on before cpufreq becomes available in its folder.
sheepkill15 said:
You can underclock with stock kernel if I know correctly.
Click to expand...
Click to collapse
Instead of what I understand, with the normal app type cpu master, or no frills cpu you can not change the clock of the CPU and the governor, but with the app Kernel Adiutor, recommended by @iloveoreos is possible, it is very strange this thing. However, despite the underclock of the CPU you can not then earn so much battery, it seems void
AntoKemz said:
Instead of what I understand, with the normal app type cpu master, or no frills cpu you can not change the clock of the CPU and the governor, but with the app Kernel Adiutor, recommended by @iloveoreos is possible, it is very strange this thing. However, despite the underclock of the CPU you can not then earn so much battery, it seems void
Click to expand...
Click to collapse
It doesn't count that much because you rarely use the cpu max freq. Maybe try underclocking the gpu too, if you can but probably not and there's not much else to do
AntoKemz said:
Instead of what I understand, with the normal app type cpu master, or no frills cpu you can not change the clock of the CPU and the governor, but with the app Kernel Adiutor, recommended by @iloveoreos is possible, it is very strange this thing. However, despite the underclock of the CPU you can not then earn so much battery, it seems void
Click to expand...
Click to collapse
The cpu and gpu are managed by the OS and its resepective governor settings. Little will be gained by reducing cpu cylcles unless it's correctly managed.
The single biggest battery user is the screen. Either reduce the brightness to the lowest you can stand and limit its on time or use powersave mode which will reduce both screen and cpu/gpu frequency.
Also selecting a more suitable governor helps.
If you frequently use high cpu usage apps its pointless using a conservative governor as you'll just lag the device. An ondemand governor would be better suited.
You can also set apps to be killed the moment you leave them in the developer settings.
ashyx said:
The cpu and gpu are managed by the OS and its resepective governor settings. Little will be gained by reducing cpu cylcles unless it's correctly managed.
The single biggest battery user is the screen. Either reduce the brightness to the lowest you can stand and limit its on time or use powersave mode which will reduce both screen and cpu/gpu frequency.
Also selecting a more suitable governor helps.
If you frequently use high cpu usage apps its pointless using a conservative governor as you'll just lag the device. An ondemand governor would be better suited.
You can also set apps to be killed the moment you leave them in the developer settings.
Click to expand...
Click to collapse
The problem is that with the only governors we have in stock are interactive, performance and userspace. The kernel allows me to just adjust the cpu, and on android oreo we do not have custom kernels that allow me to do anything. So in addition to lowering the brightness, really there is nothing that thanks to xposed and the root that allows me to do at least 5 hours of screen? The upgrade to oreo ruined everything, Nougat was too perfect