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

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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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14 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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37 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
890 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
18 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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31 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. ...
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1answer
52 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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1answer
72 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
33 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
44 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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165 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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2answers
169 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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116 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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236 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
207 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
31 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
199 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
107 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
34 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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1answer
49 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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0answers
73 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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2answers
438 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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1answer
119 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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1answer
124 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
27 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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121 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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55 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 ...
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3answers
332 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 ...
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2answers
413 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 ...
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1answer
55 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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1answer
297 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
91 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 ...
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1answer
204 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 ...
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5k 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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228 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 ...
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1answer
414 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
276 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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3k 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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71 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 ...
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646 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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26 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. ...
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81 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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49 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 ...
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156 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
66 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
74 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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171 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 ...
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93 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 ...
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802 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 ...
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264 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 ...