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

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41 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 ...
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0answers
41 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
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1answer
51 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 ...
7
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1answer
181 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
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3answers
924 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
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1answer
26 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
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1answer
74 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 ...
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3answers
50 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 ...
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2answers
77 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), ...
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1answer
23 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
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1answer
151 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 ...
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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
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1answer
54 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 ...
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0answers
28 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
139 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 ...
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1answer
57 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
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2answers
59 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 ...
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3answers
83 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
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1answer
55 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 ...
7
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1answer
306 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
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0answers
152 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
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1answer
209 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
367 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
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2answers
502 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
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1answer
178 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 ...
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1answer
138 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
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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
430 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
6k 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 ...
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0answers
103 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
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1answer
128 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 ...
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1answer
196 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 ...
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2answers
310 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
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1answer
146 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
300 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
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1answer
196 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
82 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
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3answers
220 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 ...
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2answers
1k 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 ...
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0answers
85 views

at daemon creates empty tasks

I have problem with atd daemon. If at is called by non-root, it creates task, but it is empty (content of /var/spool/atd). I do not remember what I have done before it broke that way. What else ...
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0answers
91 views

Client-server app for sending and monitoring asynchronous jobs

I am looking for a desktop app/IDE in which you can: Maintain a list of UNIX/Linux connections Be able to write a script locally in a local editor, not SCP files to the host or writing them on the ...
0
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1answer
218 views

How to make a scheduled task based on a file creation time?

The supercomputer I run my Analysis uses SGE to do the job management and requires each job duration not longer than 24 hours. And this feature is causing me quite a headache. Sadly, I was asked to ...
2
votes
1answer
755 views

controlling priority of applications using cgroups

I would like to understand cgroups better and would like to understand the use-cases for applying cgroups. Are cgroups a good way for prioritizing different applications (i.e, giving higher priority ...
4
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2answers
696 views

How preemption works on Linux when a program has a timer less then 4ms?

Jiffies in most Linux system are defaulted to 250 (4ms). The questions is that what happens when a program has a usleep() less then 4ms ? Of course it works as should when it is scheduled. But what ...
6
votes
1answer
377 views

Why mkfifo behaves like a LIFO?

If i do. mkfifo /tmp/a echo 'one'>/tmp/a in the while from another terminal echo 'two'>/tmp/a and from a third terminal more /tmp/a Why i obtain as output of the last command this? ...
2
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3answers
1k views

Bash while loop and reading from pipe

I have a Windows command-line program that I'm running in a Bash script in Ubuntu via wine. The Bash script basically looks like this: wine myprogram.exe | while read line do # Process line done ...
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3answers
1k views

Conditional crontab command in bash script

How do I invoke a crontab command so that I can schedule to run a script with a 20 minute delay based on some condition? Edit: What if I wanted a command that schedules a script to be executed only ...
4
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4answers
609 views

How to prevent atd from running past jobs?

The at daemon is a great tool! However, if a job is scheduled for 8:00 am and the machine is off at that time, at will run the job whenever the machine is booted. What I would like to do is stop it ...
5
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2answers
919 views

Does Linux kernel 3.x use the CFS process scheduler?

Does the latest version of the Linux kernel (3.x) still use the Completely Fair Scheduler (CFS) for process scheduling which was introduced in 2.6.x ? If it doesn't, which one does it use, and how ...
3
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1answer
253 views

Unix/Linux process scheduler logs

Where can I actually see what decisions did a process scheduler make over a time period? Are there scheduling specific logs maintained by Unix/Linux systems I could take a look or should I be looking ...