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

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7
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1answer
48 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
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2answers
32 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
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0answers
32 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. ...
4
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2answers
228 views

Schedule job at irregular intervals

It's simple enough to use cron to schedule a job to occur periodically. I'd like to have something occur less regularly -- say, run the job, then wait 2 to 12 hours before trying again. (Any ...
2
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0answers
44 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 ...
2
votes
1answer
40 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 ...
1
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2answers
24 views

Meaning of PF_VCPU and PF_WQ_WORKER

do you know what the constants meaning is defined in linux/sched.h: #define PF_VCPU 0x00000010 /* I'm a virtual CPU */ #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */ What ...
0
votes
1answer
73 views

Using the Echo Command with Sleep command

So I asked a question on here a few weeks ago and the response I got was helpful but I figured I would add some info to get a better response. I work with a computer system that has 8 servers (4 ...
3
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2answers
35 views

Trigger job only once and only when load is low

I'd like have automatic update of my gtags, but only when the system is idle. To achieve this, I'm using iupdate to watch over the interesting parts of my source folder. But I have a problem with the ...
2
votes
3answers
167 views

Is there a way to make your process use less CPU?

I want my device to use less CPU to save battery. I have a program that uses a large amount of it. nice won't help as all it does is change scheduling when CPU is at %100, while I don't want it to get ...
1
vote
2answers
176 views

Which process scheduler is my linux system using?

I'm not quite sure if stackoverflow or serverfault is the forum to use for this question, but ill try here. Is there some command I can use or a file I can check in order to find out which process ...
1
vote
1answer
49 views

Can a real-time process exist in the 'expired' queue of linux kernel?

In the Linux kernel 2.4: Real-time processes are given a priority of 0-99 and they co-exist in the ready queue along with the nice processes (who's priority goes between 100 and 139). But real-time ...
2
votes
1answer
193 views

Why isn't the -rt (RT-Preempt) kernel patch included by default in the mainline kernel?

According to https://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO , the RT-Preempt patch converts Linux into a fully preemptible kernel. The magic is done by: Making in-kernel locking-primitives ...
3
votes
1answer
63 views

What's the easiest way to set up a 2-hour alarm?

I want my computer to play some given .mp3 every 2 hours. I want it to run at startup, and be modifiable with a given .conf file. The choice of .mp3 will also be in the .conf file. The reason is, I ...
9
votes
1answer
192 views

Cronjob to Run and then Terminate

I want to add a cron entry that does something like: 00 00 * * * * /tmp/script.sh Is there something I can add to the end of the line, so that when it is finished, it will remove the line out of my ...
6
votes
3answers
1k 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?
2
votes
1answer
101 views

How to display next schedule time for a TSM node?

0:root@SERVER:/SERVER/fs_111 # dsmc q schedule IBM Tivoli Storage Manager Command Line Backup-Archive Client Interface Client Version 6, Release 4, Level 0.1 Client date/time: 03/09/2014 ...
2
votes
1answer
141 views

What is the recommended way of setting a default IO scheduler on Linux?

I would like deadline to be the default IO scheduler for my system, and I don't want to lose that config when I reboot. What is the proper way of doing that? (I'm using Debian) Some hints: have a ...
2
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3answers
132 views

Starting Linux from power off at predetermined time (and executing command)?

To put it simply, I'm trying to use my computer as an alarm clock. It's slightly old and noisy, so I'd like it to start from power off at a scheduled time and then execute a command, such as playing ...
0
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2answers
506 views

Cron job is not working [closed]

i have a cron job center code hereonfigured at var/spool/cron/testuser, Am calling "adindex.sh" file from there. Am getting results when am directly put the command directly in prompt(php and sh), ...
1
vote
1answer
54 views

How does handling an interrupt affects a multi-threaded user space process?

Say, I put a breakpoint (int 3 from now on) somewhere in a user space process code. One of the threads hits the breakpoint... And what happens next? My judgement is: this is an interrupt, so it is ...
3
votes
1answer
389 views

chrt(): “failed to set pid XXX's policy” on one machine, but not others

I have several Linux machines, all of them running the same kernel (Ubuntu 12.04, 3.5.0-45-generic). On one of them, I am unable to use chrt at all. If I attempt to use it on a new process, I get the ...
0
votes
1answer
24 views

Are the crontabs of users linked?

Our Linux server has a community user that has a crontab for itself. The admins don't want me to schedule my scripts on their crontab because they don't want to take responsibility for my programming. ...
1
vote
1answer
68 views

Execution behaviour of cron

I want to schedule a cron so as to avoid running at midnight. I was thinking a period of 7 minutes. Now, I figured out with 7 minutes of interval, the last cron schedule for a particular day would be ...
0
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0answers
36 views

How do I interpret an entry about cron in Gnome System Log Viewer

Apologies if this turns out to be a trivial question. I am trying to set up a regular backup of my files prior to installing Fedora 19 instead of my current Fedora 12. In November 2013 I started a ...
6
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2answers
148 views

Why are there so few “running” processes?

On all of BSD/Linux/MacOS and Solaris, I made an observation - no matter how busy the system is, top always reports very few (usually 1-2) running processes. According to my limited understanding, a ...
1
vote
1answer
64 views

I/O brings a machine to its knees [closed]

Why, on every Linux I've used, when a program is really I/O bound, it bogs the machine down? It just happened when I (accidentally) tried to make gcc compile a (valid!) 50Mb C file. GCC was so I/O ...
2
votes
2answers
65 views

How can I automate a task on a certain event?

Playonlinux and WINE are great. Finally I can have my favourite games and the joys of Linux without having dual-boot or filling my disk with Windows crap! But some are quite old, and only run on lower ...
3
votes
3answers
116 views

stopping atd job at specified time

I'm trying to schedule download at nights. I have created a atd job which starts download script at 2 AM. Now I want to stop the same job at 7 AM if it is still running. What I'm doing now is just ...
0
votes
1answer
72 views

Replace my recurring task scheduler with some existing product

I have a couple tasks that I like to run periodically: Push all git repositories (5 times a day) Do a virus scan on files (every 90 days) Download backup from server (one a day) For all those ...
8
votes
1answer
537 views

How is nice working?

sched_setscheduler says : All scheduling is preemptive: if a process with a higher static priority becomes ready to run, the currently running process will be preempted and ...
2
votes
0answers
208 views

how to stop kernel threads preempting real time user space processes?

I created some processes in user space and tried to visualize its working in kernelshark with the trace recorded using trace-cmd. But kernel processes like the ones shown below are preempting my ...
3
votes
1answer
345 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 ...
2
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2answers
666 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?
2
votes
2answers
803 views

Can system calls be interrupted?

Please comment on the following sentence: On the standard Linux kernel without the rt patch, interrupts can't interrupt ongoing system calls. The reason why our machine doesn't stop working ...
2
votes
1answer
357 views

Are time interrupts always followed by a scheduler call?

When a timer interrupt occurred the ISR is called to service the interrupt. Is it okay to assume that every timer interrupt ends with a call to the scheduler on which process should continue running ...
1
vote
1answer
218 views

Run command after nice command has finished

I have 3 nice commands that are dumping some databases, and compress assets for a backup. After that, the files should be copied to another server. I'm using this command: nice mysqldump -u user1 ...
0
votes
1answer
38 views

Is there such a scheduler and is it feasible?

I read about a scheduling algorithm called EDD which always works on the next deadline and that is feasible. Would it also be feasible to within each time windows or slice, work on all processor or ...
4
votes
1answer
665 views

How is cron scheduling actually implemented and makes sure scripts run on time?

I want to ask about cron jobs. OK, we place the scripts in the crontab and the cron daemon executes them. Now if I understand this, each minute, cron checks the crontab of each user and executes the ...
3
votes
2answers
9k 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 ...
2
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0answers
122 views

So the design of client-server separation is not the bottleneck of X Window?

In the answer of this, it mentioned: People also hear that X uses the "network" and think this is going to be a performance bottleneck. "Network" here means local UNIX domain socket, which has ...
1
vote
1answer
173 views

How to trace process scheduling of certain process?

For a project at my university I am researching ways to trace, log and manipulate the process scheduling of certain processes. I would like to launch an number of applications, everyone in a single ...
1
vote
1answer
259 views

Do kernel counters for jiffies in state exist in Linux?

I am looking to get time/jiffie stats on the state of a daemon process. The states I'm referring to are mentioned in the Linux Kernel Proc Filesystem document. Running, Sleeping, uninterruptible ...
1
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2answers
516 views

Run a command at a certain time in cygwin

I am writing a bash (.sh) script for cygwin. I want to run a certain command at specific time. I tried the following: echo "test" | at 19:00 but I get the following error: The AT command has been ...
2
votes
1answer
209 views

Are threads which are executing blocking system calls awoken by interrupts?

I've been reading a bit about threads and interrupts. And there is a sections which says that parallel programing using threads is simpler because we don't have to worry about interrupts. However, ...
2
votes
3answers
492 views

How can I schedule a python program to run from another python program?

I'm running a Python program on my Linux server, and depending on some external data it has to run again at xx minutes or hours from now. So let's say it runs at 6 AM, and then it has to run again at ...
2
votes
1answer
225 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 ...
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votes
2answers
88 views

Which Linux distro/mode offers lowest interference when running your own applications?

I'm interested in a Linux distro to build C projects and test their behavior in a very predictable and controlled environment. I'm especially concerned about letting the scheduler deal as much as ...
2
votes
3answers
367 views

scheduling background tasks in succession

I've got three SAS programs to run in the background over a weekend. The three programs output information into files of the same names, so I'll need to remove these output files after the first ...
5
votes
2answers
2k 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 ...