Which io scheduler android

Good question! I have always wondered this. If anyone knows, or can explain the differences I'd be interested. Quote from: Grebbin77 on March 15, , pm. It was recommended a while ago but I can't who said it. Always works great for me. As far as governors go- of course a Conservative governor will slow things down but when it comes to the "Interactive Vs Performance" debate, I've never really gained by using the latter.

In fact, for native Android games, holding the CPU at max has cause me to experience microstutter but I could swear by the Interactive governor and the versatility it offers. Skelton-retired Posts: There are no big differences between governors and schedulers. Anyway, we are talking about minimal differences, there isn't a huge change in behaviour. I personally never noticed microstutter in android games using performance, but I never suffer it with other governors either.

There is no perfect combination anyway, is just testing and depending on the emus or games you play, just use that according to your needs.

Just what I was looking for.. And then!!! Everytime i confuse about these things, i always read this site Helpful thanks. Very nice article. Post a Comment Please respect the admin of the website and don't post spam! Spam will be removed through moderation so you will be wasting time if you do so! Post something meaningful that will help the developer or others : If spam becomes a problem, I will remove the ability to create comments once again. Kernel Adiutor Free to change scheduler and tune variables 2.

Kernel Adiutor-Mod Free to change scheduler and tune variables 3. Compatible kernel managers e. This pages includes: - Descriptions - Recommendations - Comparisons - Graphs - Tunables Note to people who want to reuse this information: There have been a few websites that have included my information in their own threads. Please make sure to get appropriate credits to the original authors including myself that way there will be less problems!

Read the policy for more information. To give a share of the disk bandwidth to each running process. To guarantee that certain requests will be issued before a particular deadline. Which schedulers are available? Speed - Some schedulers are known to be slower than others and some faster. A number of factors can affect speed including the simplicity of the algorithm used in the scheduler or the prioritisation of certain requests e. Stability - Older and simpler schedulers like Noop are usually more stable than newer and complex schedulers.

Smoothness - Often confused with speed, it refers to how "smooth" or the lack of delay that occurs when switching between apps or navigating throughout the UI. An scheduler that is fast may not necessarily be smooth.

Each per-process queue contains synchronous requests from processes. Time slice allocated for each queue depends on the priority of the 'parent' process. CFQ is better suited for traditional hard disks, however it may give better throughput under some situations. Deadline: The goal of the Deadline scheduler is to attempt to guarantee a start service time for a request.

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. If you want good performance, you should try deadline. In mobile devices we won't have as much parallel threads as on desktops. Benefits: - Faster UI navigation and better overall phone experience - Faster boot times and app launch times Disadvantages: - Not great for heavy multitasking - Slower write speeds The bottom line: It is a good all-round scheduler despite being biased to read operations. Your device may feel more responsive after selecting ROW because it was designed for mobile devices.

Older devices may see more of a boost in performance compared to newer devices. No priority queue concepts, but only basic merging. No reordering or sorting of requests. Benefits: - It is simple and stable. People who want better performance should avoid using this. Best used with storage devices that does not depend on mechanical movement to access data yes, like our flash drives. However older devices may experience slower performance when selected.

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: - Generally excels in random writes.

Disadvantages: - Performance variability can lead to different results Only performs well sometimes - Sometimes unstable and unreliable The bottom line: Not the best scheduler to select.

You will probably find that other schedulers are performing better while being more stable. 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 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. Benefits: - Same as Noop, but can be beneficial to kernel developers Disadvantages: - Same as Noop The bottom line: Shouldn't really be used by anyone. You should be using Noop instead of this. 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. It will continue to improve with more development. It's basically a cache for files that have been opened recently on your mobile device, so that they can be quickly accessed again if needed.

By android default, this value has been set to kB. Have a look at the graph below:. Any setting above what I have recommended may yield no extra performance!

If you have issues such as failed reads and writes after changing these values, try a smaller value. Please note that some SD cards may experience issues after setting a higher buffer value.

What to remember: - More isn't always better! Thanks haldi for the graphs! IO Scheduler Comparison. Multitasking performance:. 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. The default is Either it fits in the back of that request, or it fits at the front.

Typically back merges are much more common than front merges.