A technique for scheduling tasks to be run at a specific time or on a specific event.

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3
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2answers
502 views

PBS equivalent of 'top' command: avoid running 'qstat' repeatedly

When I run several jobs on a head node, I like to monitor the progress using the command top. However, when I'm using PBS to run several jobs on a cluster, top will of course not show these jobs, and ...
4
votes
1answer
210 views

Is it possible in taskwarrior for reminders about recurring tasks to expire automatically?

I'm using taskwarrior. I want to be reminded of something every week, but have that reminder go away automatically if I haven't completed it by the time the next week comes up. (Or, actually, I want ...
3
votes
1answer
931 views

Using sched_rt_period_us for setting maximum time between task calls of order of 10ms

I realize sched_rt_period_us and sched_rt_runtime_us are meant to prevent freezing the system in case of runaway RT task. I wonder though, if it's possible to use a small value of sched_rt_period_us ...
0
votes
1answer
12 views

Are blocked and blocked/suspend processes put into the same queue?

In a 7-state process model (new, ready, blocked, running, blocked/suspend, blocked/ready, exit), are processes in the blocked and blocked/suspend states for each event that processes are blocked on ...
5
votes
3answers
68 views

How can I verify `nice` is working?

Looking at different jobs running on a system with shared resources, it seems the nice values are being ignored. Many jobs with nice set at 19 are running at 100% cpu load while other many other jobs ...
1
vote
0answers
12 views

How to set a process’s sched method to fifo and priority when cgroup are on?

I’m using CentOS 6.6, I want to set the sched method of my kvm VM to FIFO with priority 1. First, I use chrt and get error: chrt(): "failed to set pid XXX's policy" I find here: chrt(): ...
25
votes
3answers
114k views

How can get a list of all scheduled cron jobs on my machine?

My sysadmin has set up a bunch of cron jobs on my machine. I'd like to know exactly what is scheduled for what time. How can I get that list?
2
votes
0answers
86 views

Configure job to expire

I'm learning Linux at the moment and were doing some exercises scheduling jobs with cron and crontab, but I'm wondering if it's possible to limit the amount of times that the scheduled job is ran. ...
3
votes
0answers
31 views

Why does Linux scheduler have locks for run queues?

Why does Linux Kernel Scheduler code have locks for run queues? Does the scheduler spawn kernel threads, and locks are to prevent two of such threads to avoid modifying run queues at the same time?
1
vote
1answer
39 views

Why doesn't the Linux kernel prioritize interactive programs?

I've noticed that when running at 100%, things like GNOME become less responsive until I kill background tasks that are expected to take a long time, like compilation or downloading email. Why ...
1
vote
1answer
43 views

Why have the notion of 'nice'?

I know what 'nice' is and how it maps to priority, this is not the question. Linux priorities range from 0-139. 0-99 is real time, 100-139 is user space. Nice maps onto priority: -20 → 100 0 → 120 ...
0
votes
1answer
29 views

Midi and Scheduler on Linux / Raspberry Pi

I'm fairly new to MIDI and Linux. I have an Akai MPX8 with a bunch of individual WAV files loaded onto it. The WAV files play well over the existing audio system. The audio files are launched by ...
0
votes
0answers
57 views

CPU Scheduling incredibly slow with large difference between total execution time and actual CPU time - Ubuntu Full-Disk Encryption enabled

Admittedly, I am running on a build that is no younger than five years old at this point and the system is not going to be incredibly fast. However, at the same time, the run-times I am observing are ...
2
votes
1answer
52 views

How to schedule shutdown every day?

We have a server that is used for Linux thin clients in a class. The server is started when required and I want to schedule it to power off at 22:00 every day to avoid power wasting. I thought of ...
1
vote
1answer
108 views

Why sudo user can use sched_setscheduler SCHED_RR while root can not?

I am running Arch Linux on a Raspberry Pi 2. I have a user-space program that uses Gordon's wiringPi library and, in particular, the piHiPri() function that attempts to set the highest priority for ...
0
votes
3answers
77 views

how to tell crontab to execute the command from now instantly

I have a command in "/etc/crontab" which runs a database program every 7 days. Now, I see that this command has been commented by another user for 2 weeks. I immediately uncommented the line, and ...
0
votes
1answer
41 views

How to skip email notification for at command in AIX?

(AIX 6.1 ) man page for at says -m option could send an email to the user. But this is the default behavior, even without specifying the -m option. Is there a way to turn this off, I do not want mails ...
7
votes
3answers
5k views

Is there a workaround for a lack of scheduler in qbittorrent?

Unlike many other torrent clients, qbittorrent comes without a scheduling tool. Ideally, one can throttle downloads over a certain time of the day, on given days. Is there a workaround for this? Is ...
2
votes
1answer
132 views

Relationship between IO scheduler and cpu/process scheduler?

The concepts of IO scheduler and CPU scheduler confuse me. Below are my understanding: Linux uses CFS scheduler + nice values by default to schedule processes. Each process has an IO queue. There ...
2
votes
1answer
315 views

Run script every 30 min with systemd

I would like to execute a script every 30 min after booting into the system. I know you can use cron, but I don't plan to use this feature often therefore I'd like to try it with systemd. So far I ...
0
votes
4answers
190 views

cron - production-ready alternative

I am testing out a Raspberry Pi with the aim to use it in a production system for logging manufacturing data. All is working well and I have been recording test data over the last month. For ...
2
votes
0answers
173 views

Catch the kill signal when a process is in S state [interruptible sleep]

This is the process group : (ps -ejH) xxxx xxxx xxxx ? 00:00:00 sshd yyyy yyyy yyyy ? 00:00:00 sshd 8713 8713 8713 pts/0 00:00:00 bash 1234 1234 1234 ? ...
0
votes
1answer
34 views

Scheduling gFTP Download

My current set up involved two HP laptops running Linux Mint 13 (one 32-bit, the other 64-bit) and a Mint 13 server in the cloud. I have been using gFTP for transferring files without problem. However ...
1
vote
1answer
31 views

Is there a good reason to prevent users from using cron/at?

At work on our linux servers, I have a standard non root account. Unfortunately the account does not have permissions to crontab or at. Is there a good reason to block these commands? I can write a ...
1
vote
1answer
88 views

What is the functionality of SCHED_SOFTIRQ in linux?

Who raises this softirq? Is it raised on every time tick( based on timer interrupt?) Does this make the kernel to shedule a runnable process? If yes, how does the handlers of lower priority softirqs ...
5
votes
3answers
18k views

What does “INFO: task XXX blocked for more than 120 seconds” exactly mean on Linux?

I had this message in my kernel log : INFO: task XXX blocked for more than 120 seconds. I would like to know what it means technically: under what conditions does the kernel display this message about ...
3
votes
1answer
350 views

What makes the Linux scheduler seem unpredictable?

The question refers to the output of a multi-threaded application, where each thread merely prints its ID (user assigned number) on the standard output. Here all threads have equal priority and ...
15
votes
4answers
24k views

How to shutdown Linux at a specific datetime from terminal?

It seems I can shutdown using sudo shutdown by specifying a time or minutes. Is there a way to specify datetime for shutdown?
1
vote
1answer
41 views

take the DRAM performance of the processes into consideration when scheduling

The CFS scheduler in Linux schedules the processes based on the virtual runtime of CPU. But, the DRAM memory is the bottleneck in most of the emerging domains. Why not take the DRAM performance of ...
7
votes
5answers
1k views

Can you make a linux system halt and boot my Raspberry-pi at certain times?

How to make a system turn itself off and back on at different times. For example I would have my "server" turn off at 4 A.M then turn back on at 5 A.M every day. Is this possible? I am using a ...
0
votes
0answers
46 views

Linux Fedora 20: how can I find out what is happening behind the scenes

I have Fedora 20 installed, using MATE desktop and zshell and something weird is going on. I get lots of odd unexplained beeps from my speakers, even though the volume is turned down to zero, so ...
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vote
0answers
24 views

expanding the priorities table in runqueue in Linux kernel

I have a hw assignment that I'm having really hard time with, probably since I'm new to the whole Linux kernel thing. we're supposed to add a new scheduling policy to the existing scheduling ...
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0answers
24 views

Spawning processes on a job stack

I have a hobbyist server on which I want users to upload a file, and then receive the overcome of some processing (server-side) over the given file. I am doing the processing synchronously so that for ...
3
votes
1answer
115 views

Thread process in linux

I'm wondering about the "punishment" that occurs when a new thread is created. From my understanding of clone(2), NPTL (New POSIX Thread Library), CFS (Completely Fair Scheduler), when a new thread ...
3
votes
1answer
170 views

Why does the 'user' and 'sys' time vary on multiple executions?

There is a nice question and answer explaining the relationships between 'real', 'user' and 'sys'. It explains the reasons why 'real' can vary, and defines the 'user' and 'sys' as times the process ...
2
votes
1answer
265 views

Enable BFQ in Fedora

I am running Fedora with the stock kernel and I'd like to enable the BFQ disk I/O scheduler, and ideally BFS. I have built my own kernel and that works, though it is a royal pain dealing with the ...
1
vote
1answer
38 views

Run program while computer is cool

I'm trying to compile a program on a computer with inadequate cooling. The program, specifically, is the linux-ck kernel with -mtune=native march=native processor-specific optimizations, so simply ...
1
vote
1answer
65 views

High precision scheduler daemon

I'm looking for a scheduler daemon like cron, but with at least seconds precision so I can use it for a radio automation app. I've heard conflicting rumors about cron's ability to handle seconds. If ...
4
votes
2answers
472 views

How is the real-time priority of a process set by default?

I understand that, for scheduling purposes, Linux processes have a "nice" value and a real-time priority value and that these can be explicitly altered with the nice and chrt commands. If the user ...
1
vote
0answers
679 views

Does the timeslice depend on process priority or not under Completely Fair Scheduling?

I'm trying to understand the Completely Fair Scheduler (CFS). According to Robert Love in Linux Kernel Development, 3rd edition(italics his, bold mine): Rather than assign each process a ...
5
votes
1answer
150 views

Is the Unix process scheduler itself a process?

Is the Unix process scheduler itself a process, or does it piggyback on other processes in the same way a system call does (running kernel code in the user process with the kernel bit set)?
1
vote
1answer
74 views

What is the scheduling algorithm of the Native POSIX Thread Library?

According to Wikipedia, The Native POSIX Thread Library (NPTL) is: a software feature that enables the Linux kernel to run programs written to use POSIX Threads efficiently. Which algorithm is ...
3
votes
1answer
252 views

Which process scheduling algorithm is used by Linux?

The Linux operating system switches between running processes to enable multi-tasking. What algorithm is used to determine when to suspend the execution of the currently running process and which ...
6
votes
1answer
2k views

Real time processes scheduling in Linux

I have been learning some scheduling concepts. Currently my understanding so far is as below. There are real time processes and non real time processes. Non real time processes can have nice values ...
2
votes
1answer
2k views

Why highest priority threads are displayed with RT in top and htop?

In the top and htop tools, processes (or/and threads depending on display settings) having the highest realtime priority (99 from the userland API point of view) with either the scheduling policy ...
2
votes
2answers
2k views

How to install and use at job scheduling?

I am not clear on the following: Is the process for at available to all linux installations? Or do would I need to do something to "install" it?
1
vote
2answers
43 views

How do I make “at”-tasks repeat at a specific time?

I want to schedule a script to run every Monday at 9am. How can I do this? I can only find examples for given days, not repeating things with at. Cron is not a solution.
10
votes
1answer
251 views

What does a computer actually do with its spare CPU cycles?

When a computer is not running at full load, in the context of Linux, what does it actually do? Between scheduled threads, if there is nothing to do, does it spin wait? Does it enter some sleep state? ...
0
votes
2answers
177 views

How to set cron job for system

I'm really new on Linux and have no any previous experience on it. And I opened this account to ask this question. I need to install a cron job I've followed the short guide here. Well, I think it ...
2
votes
0answers
161 views

What is the minimum round robin scheduing interval supported by Linux?

For some reason, I want to have 10 processes share the same CPU core by affinity. As you know, to achieve CPU sharing between processes, we can exploit the Linux round robin (RR) scheduling policy. ...