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

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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
106 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
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1answer
775 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 ...
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3answers
4k 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
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
39 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
99 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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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?
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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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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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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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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
44 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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3answers
15k 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
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1answer
319 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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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?
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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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5answers
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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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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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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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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 ...
3
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1answer
87 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 ...
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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
127 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
209 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 ...
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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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2answers
345 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 ...
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482 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 ...
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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
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 ...
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202 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 ...
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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
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?
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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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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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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 ...
2
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0answers
127 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. ...
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696 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 ...
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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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8answers
81k 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?
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2answers
95 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 ...
0
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1answer
192 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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3answers
453 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 ...
2
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1answer
390 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 ...
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687 views

how to queue a command to run after another command finishes?

Sometimes I start a program that takes a very long time to finish (emerge), then realize that I should go to bed instead of waiting for it. If I know this in the first place I would run program; halt ...
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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 ...