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

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7 views

Sequential process execution? [on hold]

How do I create multiple processes and run them in a certain sequence? The scheduler should not switch context. I am running a set of at least hundred programmes which must repeat after sometime while ...
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1answer
21 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 ...
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0answers
10 views

How is a process state updated to blocked state (TASK_INTERRUPTABLE)? [migrated]

When a process is waiting for IO, how is the task state updated to TASK_INTERRUPTABLE (that is, blocked)? Imagine this case, a process issues an IO request to a block device. According to my ...
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1answer
40 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
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1answer
89 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 ...
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4answers
100 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 ...
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0answers
89 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 ? ...
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1answer
23 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 ...
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1answer
30 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 ...
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1answer
46 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 ...
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1answer
33 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 ...
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0answers
23 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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44 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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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 ...
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0answers
21 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 ...
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0answers
107 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 ...
2
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0answers
58 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
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1answer
89 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
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1answer
129 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 ...
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1answer
36 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 ...
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1answer
55 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 ...
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0answers
488 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 ...
4
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2answers
352 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 ...
5
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1answer
136 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)?
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1answer
1k 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 ...
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1answer
1k 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 ...
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2answers
39 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.
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1answer
221 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? ...
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2answers
148 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 ...
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1answer
60 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
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1answer
205 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 ...
2
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0answers
128 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
votes
2answers
704 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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1answer
210 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 ...
3
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2answers
345 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 ...
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2answers
33 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 ...
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1answer
194 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 ...
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2answers
97 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 ...
3
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3answers
455 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 ...
2
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2answers
1k 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
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1answer
64 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
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1answer
392 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
156 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
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1answer
207 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 ...
12
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4answers
16k 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
545 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
734 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
457 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
4k 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
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1answer
96 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 ...