Questions tagged [scheduling]
A technique for scheduling tasks to be run at a specific time or on a specific event.
0
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2answers
22 views
reducing scheduling time of a single process
I have a process that is mining a private blockchain and it takes 100% of the CPU. I don't need that much computing power for this, so in order to reduce my energy bill I need to configure this ...
2
votes
1answer
36 views
How to make a system suspend and resume on schedule?
I have a Linux server that's only needed at workdays in work hours.
There's no point having it powered on all the time.
How can I make a Linux system suspend and resume on set times and days without ...
1
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2answers
17 views
How to test two identical process with different scheduling policy and their cpu usage
what would be the best approach to compare usage of the processor (in %) for two identical processes with different scheduling policy in for example one-minute time frame.
I'm pretty new to the linux ...
1
vote
1answer
51 views
What timezone does the `at` command use?
I've searched in the man pages for the at command there are no mentions of timezone or tz. There is this:
The exact definition of the time specification can be found in /usr/share/doc/at-3.1.10/...
2
votes
1answer
32 views
How does the kernel assign the nice value to a process after it has been executed?
The Linux kernel implements two separate priority ranges. The first is the nice value, a number from –20 to +19 with a default of 0.
Nice values are the standard priority range used in all Unix ...
0
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1answer
16 views
Is it possible to schedule an anacron single line command execution instead of sourcing a file?
Everywhere on the internet, in articles or tutorials (in the searching of "schedule an anacron command"), I find a format such as the following:
@daily 15 rsync.daily /bin/bash /home/steven/...
0
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0answers
38 views
Run and close a file every few minutes
I need to play an audio file and after 3 minutes close it, then all over again. play it 3 minutes and close it.
Currently I'm using a cron job to open the file in VLC and close it, but it's not good ...
1
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0answers
148 views
How to set the SCHED_RR time slice or time quantum per process / thread?
The time slice (also called time quantum) for threads with SCHED_RR policy can, according to the sched_rr_get_interval man page be obtained using
int sched_rr_get_interval(pid_t pid, struct timespec *...
1
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1answer
62 views
Realtime, SCHED_FIFO, CPU_SET()
I'm trying to assign two real time processes to two cpus(one each). I'm using SCHED_FIFO scheduling policy.
I'm doing the following things:
adding "quiet splash isolcpus = 6,7" at ...
1
vote
2answers
67 views
Slurm like alternative for localhost
I have resources (e.g. GPU) I can only use once at a time. When performing experiments I always need to know on time of a batch files creation, what experiments I want to execute in the future. But I ...
0
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0answers
193 views
rcu_sched self-detected stall on CPU + watchdog: BUG: soft lockup - CPU#3 stuck for 22s
Being unable to ssh into a machine I connected it to a monitor and found the following:
The machine is running Ubuntu Server 18.04 LTS and is a first generation 8 core Ryzen 1700. I've restarted the ...
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0answers
23 views
Determine average and maximum execution time of a task by using ftrace/perf
I've gathered some traces containing scheduling events ('sched:*') by using ftrace and perf record. By analyzing the results many of my questions could already be answered.
However, I was wondering ...
2
votes
1answer
82 views
How can I visualize the scheduling domains on Linux?
It seems current versions of Linux use scheduling domains to distribute processes between CPUs, hyperthreads, NUMA nodes, etc.
Say I wanted to visualize the domains that exist on a system, and some ...
3
votes
0answers
284 views
ext4 jbd2 and I/O priority
I want to delete a huge directory with over 6 million files across over 4000 directories, totaling about 26GB of data. As I knew this was going to take a while I used ionice to set the I/O priority ...
0
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0answers
61 views
Range of values of virtual runtime in CFS scheduler
I am trying to understand the working of the Linux CFS scheduler using kernel version 4.19.2.
As mentioned in the documentation, it does not use timeslices in the traditional way but uses the concept ...
1
vote
3answers
369 views
What's the advantage of mere Ansible on mere shell-scripting if one doesn't use communally-maintained Ansible-Galaxy roles? [closed]
I establish a LAMP with a few extras on a remote Debian machine with a similar shell (Bash) script:
#/bin/bash
apt update -y
apt upgrade ufw sshguard unattended-upgrades wget curl git zip unzip tree ...
0
votes
1answer
48 views
change a value in a file
I have a configuration file that some of its lines is like below:
# Mandatory: no
# Range: 0-5
# Default:
DebugLevel=3
I want to change the 3 at DebugLevel to 5 at 2 AM then after for example 2 ...
0
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0answers
28 views
ionice vs nice for mysqlimport
I am trying to import a huge .sql file into a mysql server.
What (if any) is a best option to speed up the process (all other parameters being equal)
reducing the process niceness to -20?
setting ...
0
votes
1answer
48 views
Is it possible have a deterministic run of linux process inside docker?
Imagine that I have a linux program that does some network IO. Execution of the program is not deterministic: it gonna produce different results depending on how it's threads are scheduled, what ...
1
vote
1answer
306 views
What's the process scheduler in Linux?
I read wikipedia about process scheduler:
The process scheduler is a part of the operating system that decides which process runs at a certain point in time.
I don't really understand what that ...
1
vote
1answer
112 views
Restrict time of day for anacron jobs in Linux Mint
I'd like to restrict the time of day the jobs set in anacrontab are allowed to run.
I can find in man pages online info about START_HOURS_RANGE which is supposed to do precisely that. For example ...
0
votes
0answers
12 views
Thread scheduling behavior between steps of GDB compared to non-stepped execution
The GDB manual states that when using all-stop mode for debugging a multithreaded application, it is not possible to advance every thread in lock-step by exactly one statement. This makes sense since ...
0
votes
1answer
384 views
How to schedule to run testng.xml file on terminal on linux environment?
I have scripted a Selenium automation testcase. I have generated the testng.xml file which should be executed on the linux terminal at a particular time of my need. Say I want to schdule to execute ...
0
votes
2answers
420 views
How to schedule a command to execute in every 2 hours?
I want to run a small monitoring jar file every 2 hours in my ubuntu machine.
java -jar mymonitoringtool.jar
I don't know how to set it up.
-2
votes
2answers
71 views
Why is there no choice for cooperative scheduling?
Operating System Concepts says
CPU-scheduling decisions may take place under the following four
circum- stances:
When a process switches from the running state to the waiting state (for ...
1
vote
0answers
456 views
How linux kernel scheduling works on multi core processor? [closed]
I recently started reading Robert Love's book "Linux Kernel Development 3rd edition" and dived into the scheduler part, which left me with lots of questions.
So first off, I understood there are 2 ...
2
votes
0answers
32 views
Incorrect Top? or manpage?
According to top's manpage:
16. PR -- Priority
The scheduling priority of the task. If you see `rt' in this
field, it means the task is running under real time scheduling priority.
...
1
vote
1answer
76 views
FCFS disk scheduling [closed]
I want to find head movement through Disk Scheduling first come first serve algorithm
queue = 98, 183, 37, 122, 14, 124, 65, 67
head start at 53
I have confused because this same quotation two book ...
0
votes
1answer
521 views
/proc/PID/sched measure units
Does anyone know what are the measurement units for the metrics in /proc/<PID>/sched file in Linux?
cat /proc/1277/sched
flush-202:32 (1277, #threads: 1)
----------------------------------------...
0
votes
1answer
129 views
Is it recommended to use param.sched_priority in Linux FIFO during thread creation?
In my embedded device I absorb strange behaviour with the protocol we use, sometimes it takes a while to send the data via serial device using FIFO.
My suspicion is Linux is not real-time OS and why ...
1
vote
2answers
540 views
Meaning of parameter “kernel.sched_min_granularity_ns” in RHEL6/RHEL7
While studying the kernel behaviour from RHEL6 to RHEL7, we came across an explanation on RHEL6 kernel parameters:
> kernel.sched_min_granularity_ns
sched_min_granularity_ns is the initial ...
1
vote
1answer
275 views
How does the kernel scheduler know a timeslice has passed?
In my previous question How does the kernel scheduler know how to pre-empt a process? I was given an answer to how pre-emption occurs.
Now I am wondering, how does the kernel scheduler know that a ...
1
vote
2answers
413 views
How does the kernel scheduler know how to pre-empt a process?
As far as I understand, the kernel is not a process, but rather a set of handlers that can be invoked from the runtime of another progress (or by the kernel itself via a timer or something similar?)
...
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0answers
144 views
How to keep Linux kworker threads alive?
I'm experiencing some data loss on a USB-to-serial adapter on a Raspberry Pi running at a (relatively) high data rate. I believe most of the work is carried out by kernel threads:
2569 root 20 ...
1
vote
2answers
670 views
Giving users scheduling privileges
I have some code which uses sched_setscheduler from sched.h
sched_param sched;
sched.sched_priority = 70;
sched_setscheduler(getpid(), SCHED_FIFO, &sched);
However, this function will fail ...
1
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0answers
73 views
Linux (kernel 3.x and 4.x) Pthread and general process scheduling algorithms
I was wondering if both scheduling (contention) scopes (SYSTEM and PROCESS) are used in the Linux kernel scheduling logic. POSIX supports PROCESS scope pthreads (MXN model) and SYSTEM scope pthreads (...
0
votes
0answers
7 views
sched_deadline behaviour
I've studied the sched_deadline and i have some questions:
1) Is a portion of CPU assigned to sched_deadline algorithm at precise time intervals ?
If yes, who decide how much Utilization Factor ...
0
votes
1answer
327 views
CFS and real-time policies
I'm trying to implement a real-time algorithm in Linux.
I've studied the linux Real-Time policies : sched_rr, sched_fifo.
Than i go deeper and i found the Completely Fair Scheduler.
I deduced that ...
1
vote
1answer
236 views
Does Linux 3.10 CFS have “timeslices”?
Does Linux 3.10 CFS have "timeslices"?
I am confused, because sched-design-CFS.txt clearly states:
CFS uses nanosecond granularity accounting and does not rely on any jiffies or
other HZ detail. ...
1
vote
3answers
193 views
How to schedule activation/termination of KVM/QEMU virtual mahines?
I run an IPv4 server in a Fedora virtual machine. This server hosts a git service for a group of developers and is open to the internet. As a consequence, it is confronted to hacking attempts (mainly ...
2
votes
0answers
21 views
How to check a process is running in which core? [duplicate]
I have a very computationally intensive job(single threaded) running in my system, and htop is showing one of the core is ~100% utilized. Obviously, the job is scheduled to this core. But, I am ...
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0answers
40 views
During what kinds of operations is a process considered for the 'load average'?
In general, I'm trying to understand the numbers displayed by uptime (and numerous oder commands):
$ uptime
13:40:52 up 18 days, 2:10, 8 users, load average: 0.20, 0.30, 0.64
Here, my system's ...
2
votes
1answer
1k views
Kubuntu 18.04, cron task does not load @reboot
I am running Kubuntu 18.04, and have a simple script to reset the plasmashell every time after suspend/lockscreen since there's a known bug that corrupts folder/file names upon returning from suspend.
...
1
vote
1answer
276 views
Set usb flash drive as non rotational drive
I'm trying to optimize the IO schedulers and to use a proper scheduler for rotational and for non rotational drives (different).
When I run:
cat /sys/block/sd*/queue/rotational
I get:
1 <-- ...
2
votes
0answers
285 views
Shielding CPU from scheduler - How to move bound kernel threads from cores?
Suppose I have 4 physical cores (indexed 0-3) and I'm dedicating cores 1-3 to a shield for user applications and trying to steer all system threads onto core 0. I'm following the answers here and ...
1
vote
1answer
78 views
Why will crontab not run my file at a set time, but will run every minute?
So, I have attempted to get crontab to run a node.js file at a set time everyday. I have set it up by doing crontab -e. I have tested that it runs every minute by using the below:
* * * * * //path of ...
0
votes
1answer
2k views
Custom priority value: is a pthread high sched prio positive or negative?
I’m trying to reimplement in a backward-compatible way the RobotC API from C (although some details would better fit or would be easier with C++), and trying to reimplement their multithreading API in ...
0
votes
1answer
462 views
How to troubleshoot failing cron job
I have a crontab root file that looks like this:
lab-1:/var/www/cdd# crontab -l
# do daily/weekly/monthly maintenance
# min hour day month weekday command
* * * * *...
0
votes
1answer
515 views
What happens when there is a context switch while the process is in Kernel mode?
This is my understanding:
When in user mode and a trap/system call occurs, registers are saved on to the kernel stack, switch is made to kernel mode, and trap is handled and returned to user mode.
...
1
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1answer
31 views
Does increasing the niceness of processes reduce time spent on scheduling?
Suppose a server has many long-term cpu-bound processes with no realtime requirements for those processes. Would maximising the niceness of each process reduce cpu time spent on scheduling those ...
