Question

Can you identify a real-world situation that absolutely needs the scheduling method of Android OS but not another OS?

Answer 1

AndroidScheduling

Normal Scheduling

Android depends on Linux and utilizations the Linux bit's booking instruments for deciding planning arrangements. This is additionally valid for Java code and strings.

The Linux's opportunity cut booking arrangement consolidates static and dynamic needs. Procedures can be given an underlying need from 19 to - 20 (low to high need). This need will guarantee that higher need procedures will get more CPU time when required. These level are however powerful, low level need errands that don't expend their CPU time will fine their dynamic need expanded. This dynamic conduct comes about is a general better responsiveness.

As far as powerful needs it is guaranteed that lower need procedures will dependably have a lower dynamic need than forms with continuous needs.

Android utilizes two distinct components when planning the Linux portion to perform process level booking

real-time scheduling

The standard Linux piece gives two ongoing planning strategies, SCHED_FIFO and SCHED_RR. The fundamental continuous arrangement is SCHED_FIFO. It executes a first-in, first-out booking calculation. At the point when a SCHED_FIFO errand begins running, it keeps on running until the point when it intentionally yields the processor, pieces or is appropriated by a higher-need ongoing assignment. It has no timeslices. Every single other assignment of lower need won't be booked until the point when it gives up the CPU. Two equivalent need SCHED_FIFO errands don't appropriate each other. SCHED_RR is like SCHED_FIFO, with the exception of that such errands are assigned timeslices in view of their need and keep running until the point that they debilitate their timeslice. Non-continuous assignments utilize the SCHED_NORMAL booking arrangement (more established pieces had a strategy named SCHED_OTHER).

The default Android bit is arranged to permit gather booking of continuous procedures and the document framework to control this is mounted under/dev/cpuctl.

Android utilizes two diverse planning classes (utilizing linux cgroups) bg_non_interactive and default (frontal area). The arrangement is that bg_non_interactive is low need and would maximum be able to

use ~5% of the cpu (counting all foundation undertakings) and closer view ~95%. Forground implies either an Activity or an administration that is begun foregound.

At startup Services are running in bg_non_interactive unless they have been lifted to closer view booking bunch utilizing startForeground (HMI

applications are constantly set to closer view).

Binder and priorities

The binder mechanism also propagates priorities. That is the fastener procedure called will keep running with an indistinguishable need from the guest.

JVM string and process planning

An Android framework will have an arrangement of unix forms running . Some are local procedures however numerous will be forms that run a Java virtual machine. These procedures for the most part will be multi strung, All android strings are local pthreads (no green strings). There are two approaches to change the need dealing with one by

Calling Thread.setPriority that is a piece of the standard Java API and contains an incentive from MIN_PRIORITY(1) to MAX_PRIORITY(10).As all strings are pthreads these needs will be mapped to unix process needs (MIN_PRIORITY being 19 and MAX_PRIORITY - 8).

Intelligent Job-Scheduling

Present day applications can perform a considerable lot of their errands nonconcurrently, outside the immediate stream of client cooperation. A few cases of these nonconcurrent assignments are:

Refreshing system assets.

Downloading data.

Refreshing foundation undertakings.

Booking framework benefit calls.

Booking this work shrewdly can enhance your application's execution, alongside parts of framework wellbeing, for example, battery life. JobScheduler does this planning work for you.

There are a few APIs that your application can use to plan foundation work. Boss among these alternatives is JobScheduler. The JobScheduler API enables you to determine vigorous conditions for executing errands, alongside unified undertaking booking over the gadget for ideal framework wellbeing. JobScheduler likewise offers profoundly versatile usefulness: it is reasonable for little undertakings like clearing a store, and for substantial ones, for example, matching up a database to the cloud.

Notwithstanding JobScheduler, there are a few different offices accessible to help your application plan work. These include:

AlarmManager

Firebase JobDispatcher

SyncAdapter

Extra Facilities

JobScheduler is the Android system API for booking assignments or work. It initially wound up accessible in Android 5.0 (API level 21), and stays under dynamic improvement. Remarkably, Android 7.0 (API level 24) added the capacity to trigger employments in view of ContentProvider changes.

JobScheduler is actualized in the stage, which enables it to gather data about employments that need to keep running over all applications. This data is utilized to plan occupations to keep running at, or around, a similar time. Clustering work execution in this mold enables the gadget to enter and remain in rest states longer, protecting battery life.

You utilize JobScheduler by enrolling employments, indicating their necessities for system and timing. The framework at that point smoothly plans the employments to execute at the suitable circumstances. In the meantime, it likewise concedes work execution as important to follow Doze and App Standby limitations. JobScheduler gives numerous strategies to characterize work execution conditions.

On the off chance that your application targets Android 5.0 (API level 21), we prescribe that you utilize the JobScheduler to execute foundation errands. For more data about JobScheduler, see its API-reference documentation.

AlarmManager

The AlarmManager API is another choice that the structure accommodates booking undertakings. This API is valuable in cases in which an application needs to post a warning or set off an alert at a certain time.

You should just utilize this API for errands that must execute at a particular time, yet don't require the other, more vigorous, execution conditions that JobScheduler enables you to indicate, for example, gadget sit still and charging recognize.

Firebase JobDispatcher

Firebase JobDispatcher is an open-source library that gives an API like JobScheduler in the Android stage. Firebase JobDispatcher fills in as a JobScheduler-similarity layer for applications focusing on variants of Android lower than 5.0 (API level 21).

Firebase JobDispatcher bolsters the utilization of Google Play benefits as an execution for dispatching (running) employments, however the library likewise enables you to characterize and utilize different usage: For instance, you may choose to utilize JobScheduler or compose your own, custom code. As a result of this flexibility, we prescribe that you utilize this Firebase JobDispatcher if your application focuses on a variant of Android lower than 5.0 (API level 21).

For more data about Firebase JobDispatcher, allude to its documentation and source code.

Extra Facilities

Notwithstanding the APIs and libraries portrayed above, there are likewise synchronize connectors and administrations that can empower your application, under particular conditions, to perform better and all the more heartily.

SyncAdapter

The system keeps on giving the SyncAdapter class to overseeing undertakings that match up information between the gadget and a server. Match up connectors are planned particularly to sync information between a gadget and the cloud; you should just utilize them for this kind of assignment. Match up connectors are more intricate to actualize than the libraries and APIs specified above, in light of the fact that they require no less than a phony authenticator and substance supplier usage. Thus, you normally ought not make an adjust connector just to match up information to the cloud out of sight. Wherever conceivable, you ought to rather utilize JobScheduler, Firebase JobDispatcher, or GCM Network Manager .

In Android N (API level 24), the SyncManager sits over the JobScheduler. You should just utilize the SyncAdapter class in the event that you require the extra usefulness that it gives.

Administrations

The Services structure enables you to perform long-running tasks out of sight. We suggest closer view administrations for errands, for example, playing music, which need to remain inhabitant for the client. Bound administrations additionally keep on being valuable for different utilize cases: for instance, when an administration needs to run just when a client is seeing a part or action.

You ought to abstain from utilizing began administrations that run unendingly or perform occasional work, since they keep on using gadget assets notwithstanding when they are not performing valuable undertakings. Rather, you should utilize different arrangements that this page depicts, and that give local lifecycle administration. Utilize began benefits just if all else fails. The Android stage may not bolster began benefits later on.

Extra Points

Notwithstanding the arrangement you receive, remember the accompanying focuses:

Hostage Internet Portals, VPNs, and intermediaries can posture Internet-network location issues. A library or API may think the Internet is accessible, yet your administration may not be available. Bomb smoothly and reschedule as few of your errands as could reasonably be expected.

Contingent upon the conditions you allot for running an assignment, for example, arrange accessibility, after the undertaking is set off, a change may happen with the goal that those conditions are never again met. In such a case, your activity may fall flat unexpecte