scheduler

I'm newbie on Linux Kernel. Currently, I looked into idle codes and had a quesition. When processor doesn't have any taks in their own runqueue then it may go into idle mode, specific WFI(wating for interrupt). (All I mentioned is about ARM architecture not X86. So something is wrong for X86.) After staying in WFI state, maybe other processor(not idle) want to spread their task to this, idle processor(by load balance). At that time a busy processor makes task imigrated. In my point of view, when the task is imigrated, the idle processor should wake up immidiatley to process the task. right?

Would a process with more threads on Linux have more cpu time than a process with one thread? In Linux processes and threads are described by a task struct, and scheduling is based on tasks . I found also this : When a new process is created, do_fork() sets the counter field of both current (the parent) and p (the child) processes in the following way: current->counter >>= 1; p->counter = current->counter; In other words, the number of ticks left to the parent is split in two halves, one for the parent and one for the child. This is done to prevent users from getting an unlimited amount of CPU

I was reading this article, but my question is on a generic level, I was thinking along the following lines: Can a kernel be called real time just because it has a real time scheduler? Or in other words, say I have a linux kernel, and if I change the default scheduler from O(1) or CFS to a real time scheduler , will it become an RTOS? Does it require any support from the hardware? Generally I have seen embedded devices having an RTOS (eg VxWorks, QNX), do these have any special provisions/hw to support them? I know RTOS process's running time is deterministic, but then one can use longjump

I have been reading about Linux Kernel and CFS scheduler in the kernel. I came across vruntime (virtual runtime) that is the core concept behind CFS scheduler. I read from “ Linux Kernel Development ” and also from other blogs on internet but could not understand the basic calculations behind the vruntime . Does vruntime belong to a particular process or does it belong to a group of process with same nice values . What is the weighting factor and how is it calculated? I went through all these concepts but could not understand. Also what is the difference between vruntime and *min_vruntime*?

I want to set the event_scheduler global to ON even if MySQL is restarted; how can I achieve this? SET GLOBAL event_scheduler = ON; One Way - You can set your system variables and use those variables if there is any possibility to restart your mysql. Here is link Using system variables in mysql prem You can set event_scheduler=ON in my.ini or my.cnf file, then restart your server for the setting to take effect. Once set event_scheduler will always remain ON no matter whether your server restarts. Open your /etc/mysql/my.ini file and add: event_scheduler = on under the [mysqld] section (tested

Can someone explain the differences between SCHED_OTHER, SCHED_FIFO and SCHED_RR? Thanks SCHED_FIFO and SCHED_RR are so called "real-time" policies. They implement the fixed-priority real-time scheduling specified by the POSIX standard. Tasks with these policies preempt every other task, which can thus easily go into starvation (if they don't release the CPU). The difference between SCHED_FIFO and SCHED_RR is that among tasks with the same priority, SCHED_RR performs a round-robin with a certain timeslice; SCHED_FIFO, instead, needs the task to explicitly yield the processor. SCHED_OTHER is

Spring offers the possibility to schedule and execute tasks at specific intervals using annotations, e.g. @Scheduled Is there a convenient way to unit test this behavior? Of course I could call the method of the bean myself, but I want to make sure I don't run into problems like multiple executions due to misconfiguration and so on. Other frameworks offer the possibility to fast forward the time yourself. One example is Activiti where you can call org.activiti.engine.impl.util.ClockUtil.setCurrentTime(date) to fast forward the time used by the framework. Is there something comparable in Spring

There is literally no tutorial about using Heroku Scheduler with Node.js. Assume that I have a function called sayHello() and I would like to run it every 10 mins. How can I use it in controller. In ruby you write rake function_name() however no explanation made for Node. Can I write '/sayHello' or I should do extra configuration? Philip Poots Create the file <project_root>/bin/say_hello : #! /app/bin/node function sayHello() { console.log('Hello'); } sayHello(); process.exit(); Deploy to Heroku and test it with $ heroku run say_hello then add it to the scheduler with task name say_hello .

I'm working on a Firebase Cloud Function, to send triggered push notifications. Right now my function sends a push as soon as an user triggers the "IAP" event in my app. 'use strict'; const functions = require('firebase-functions'); const admin = require('firebase-admin'); admin.initializeApp(functions.config().firebase); exports.sendIAPAnalytics = functions.analytics.event('IAP').onLog((event) => { const user = event.user; const uid = user.userId; // The user ID set via the setUserId API. sendPushToUser(); return true; }); function sendPushToUser(uid) { // Fetching all the user's device