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

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4
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1answer
1k 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
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0answers
52 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 ...
7
votes
2answers
27k 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 ...
4
votes
2answers
559 views

Are there any Workload Management subsystems for Linux?

Asked this on superuser, got no response: Can anyone tell me of the status/state of WLM (Workload Management) kernel scheduler systems in Linux? Alternatively, any user-space process goal-based load ...
4
votes
1answer
50 views

Why is nice-level ignored? (Between different login sessions — honoured if started from same session.)

When I start two CPU-eating processes with different nice-level, e.g. Process 1: nice -19 sh -c 'while true; do :; done' Process 2: sh -c 'while :; do true; done' (I changed the order of : and ...
3
votes
1answer
41 views

Process running in only one processor

I have a 40 v core machine in which a java process running. I can see that this process is running in cpu6 all the time. $watch ps -o pid,psr,comm -p 4076 Every 2.0s: ps -o pid,psr,comm -p 4076 ...
8
votes
4answers
7k 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 ...
0
votes
1answer
30 views

`cpulimit` and `nice` not effective in limiting the cpu usage of a python program that contains heavvy computations using theano

I am running a program written in python that makes heavy computations using theano. As it is a very CPU-intensive program, it is disrupting all my other activies on my laptop. For this reason I ...
-3
votes
1answer
40 views

Informatica job scheduling scripting in unix

There are 4 shell scripts: Migrate a file from path-A to path-B (unix). This script triggers one powercenter work flow. This script triggers one IDQ job. This script deletes the file from path-B ...
2
votes
3answers
156 views

How does Linux kernel find out which process to wake up during interrupt handling?

I was reading the book Linux Kernel Development on Chapter Process Scheduling. On Page 61, section Waking Up, the first paragraph reads: Waking is handled via wake_up(), which wakes up all the ...
2
votes
2answers
77 views

Start/stop a systemd.service at specific times

I want to start and stop a systemd.service at specific times. Presumably I will use a .timer unit to start the job, but is there a built in way to stop the job after a specific duration, or at a ...
3
votes
2answers
1k 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 ...
2
votes
2answers
85 views

How to setup an invisible cron job?

Is there a way to schedule a task using crontab by root user but should not be visible using crontab command i.e, crontab -l either for root user or normal users?
1
vote
3answers
106 views

Process scheduling data on linux

I am doing a project on OS and require the process scheduling data for an operating system. The data has to include the list of all processes in short-term-scheduler and long-term-scheduler along with ...
3
votes
0answers
43 views

Job queueing on a single machine

I have a shiny new server for running simulations on, with a pair of Tesla GPUs and 32 cores, running CentOS 7.2. I'd like for multiple users to be able to submit jobs to the server that get queued up ...
1
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0answers
74 views

Understanding Linux Perf sched-switch and context-switches

I've been trying to enable context switch events on perf and use perf script's dump from perf.data to investigate thread blocked time. So far the only two recording options that seem to be helpful ...
0
votes
1answer
23 views

nice command behavior when only 1 function running

I just learned the existence of nice (and ionice) which seems to be really interesting. I just want to launch a process 'p_low' with less priority than my ususal one 'p_normal'. What I was able to ...
1
vote
1answer
37 views

Cron Job Hourly Except Certain Time Frame on Friday

I want my cron job to run every hour, every day except Friday when I don't want it to run at all between the hours of 2am-9am (but hourly outside of this timeframe). Ideally, I'd like to have this in ...
0
votes
1answer
26 views

Get PID of scheduled job (using at)?

Say I want to schdule this job to be run at later time MYPROGRAM > output.out 2> error.err | at 02:00 PM Mon How can I attain its PID? surly using: echo $! will not work?
3
votes
1answer
43 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?
0
votes
1answer
53 views

Schedule a job to run in the background ( one time task scheduling using at )

Is it possible to request for a job to be run at a later specifed time in the background? This is what I have so far, nohup nice MY_PROGRAM > foo.out 2> foo.err < /dev/null | at 05:23 PM ...
2
votes
0answers
57 views

System time in Minix with best precision

I'm working on a project to modify the scheduler in MINIX 3. So to test it I need to analyse the wait time and turnaround time. To calculate the wait time I'm storing the system time when the process ...
3
votes
2answers
84 views

How does the Linux scheduler determine if a process is I/O bound or CPU bound

Adding to this question, how does the scheduler determine if a process is I/O bound or CPU bound? Mr. Love in this article, says "schedulers often employ complex algorithms to determine the most ...
7
votes
6answers
2k 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 ...
1
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0answers
48 views

Process scheduling and core allocation on big.LITTLE CPUs

Recent ARM chips, like the Qualcomm Snapdragon 810, seem to be using a hybrid architecture called "big.LITTLE" with cores of different architectures and speeds combined into one CPU. On a Linux (or ...
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0answers
26 views

How to Check next day Schedule

I check the previous day schedule from a TSM server by: q eve * * begind=-1 How to check the next days schedule?
9
votes
1answer
6k 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
29 views

How to schedule task to run everyday, if I don't know when the pc will be turned on?

So, I could use the crontab command, with: 23 0 * ... but at 23:00 my laptop can be turned off, or hibernated. In that case I want a command to be executed as soon as it will be possible. How can ...
2
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0answers
42 views

Is “top” accounting for Kernel Interrupts?

I have a simple interrupt that is triggered by a GPIO-input. The IRQ only increments a variable and returns. When I turn the frequency of the interrupts up to somewhere around 10-20 kHz, the system ...
-1
votes
1answer
167 views

Cron task scheduling and stopping after certain interval [closed]

I am managing a server which has multiple cron tasks, one of the crontab entry is like below: 51 ​*/2 *​ * * /root/backup.sh can anyone explain me what is happening here, at what time the script is ...
61
votes
8answers
134k views

Where are cron errors logged?

If I setup cron jobs incorrectly they appear to silently fail. Where should I look for an error log to understand what went wrong?
0
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0answers
18 views

Who controls the thread activity?

I know that there is a program called scheduler which controls the process activity within a system. But which part of the system controls the activity of threads within a process? By the way, do or ...
2
votes
1answer
335 views

I/O schedulers for normal harddisks

For me figuring out what is the best choice for I/O scheduler in kernel was a challenge. First I learned that it is subjective then it depends upon the filesystem you use. I know you should use ...
1
vote
1answer
136 views

Tuning Linux I/O Scheduler

I need a little help with properly tuning the Linux I/O Scheduler for spinning drives. I have a process that writes data to a huge (4-16TB) memory mapped file and is using SHED_FIFO. The kernel then ...
0
votes
1answer
131 views

iotop and ionice -p show a different class/priority for the same process

After running ionice -c2 -n7 <PID> on an I/O-intensive process (VirtualBox VM) and checking the result with ionice -p <PID> it shows best-effort: prio 7 which is expected. But when ...
1
vote
3answers
291 views

Excluding specific date and time in cronjob

I am trying to schedule a cron job where the requirement is the job has to run every day, every month and every min and every hour EXCEPT 2nd and 4th sunday of every month from 1 to 3 AM. Is there a ...
21
votes
4answers
46k 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?
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vote
1answer
161 views

cronjob at resume from suspend

using linux. I know you can do an @reboot cronjob. I want to do an equivalent thing but instead of running at reboot, running after my computer awakens from suspend. Is that possible?
4
votes
2answers
111 views

Run program x minutes after finishing

My question is kinda related to a cron job I think, but I'm not entirely sure. Say I have a script (/home/me/myscript.sh) that does something, that can take an indeterminate amount of time to finish, ...
18
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2answers
400 views

Why does niceness range from -20 to 19?

The nice command allows you to adjust the scheduling priority ("niceness") of a program. On all Unix-like systems I've used, niceness is specified by a range of integers, where -20 is the most ...
1
vote
1answer
129 views

Python script works from terminal, but fails in scheduler, to write to external drive

I am trying to use a Python script to read/write from an external disk in linux, which works fine. The problem comes when I use a job scheduler to execute the Python program. I am running all this on ...
49
votes
3answers
176k 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?
3
votes
2answers
1k 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
445 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 ...
0
votes
1answer
96 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
183 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 ...
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0answers
128 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(): ...
2
votes
0answers
150 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. ...
1
vote
1answer
74 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 ...
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vote
1answer
76 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 ...