Questions tagged [priority]
The priority tag has no usage guidance.
0
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1answer
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Can same level runlevel scripts have the same priority?
Can same level runlevel scripts have the same priority?
For instance, can say runlevel x have these 2 scripts: S10ScriptName1 and S10ScriptName2 ? If so, what is the execution order?
2
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1answer
25 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 ...
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0answers
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Understading Linux Process Priority (PR)
I have been trying to understand the linux nice and priority system, from my understanding a processes NI or nice level is essentially how friendly it is to other processes in terms of fair use of ...
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0answers
91 views
OpenBSD threads priorities
Can anybody explain how to work with thread priorities in OpenBSD?
Information about this question in MAN pages is poor, it does not give clear understanding. In particular:
sched_get_priority_min/...
0
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0answers
27 views
How do you determine the priority of Linux system processes?
I've currently inherited some legacy code in which the user program spawns two threads running at priority level 49.
Here's a snippet for one of the threads:
SchedParam.sched_priority = 49;
if(...
2
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1answer
171 views
Among these two in my ps output, which real-time process will be preempted over the other by linux?
I have got some idea from: https://stackoverflow.com/questions/8887531/which-real-time-priority-is-the-highest-priority-in-linux about how the real time priority values assigned to different ...
2
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0answers
31 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.
...
0
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1answer
98 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
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1answer
35 views
Beside username and password, what information are involved in permission management of journal filesystem?
In journal filesystem(for example ext4, XFS, ZFS, JFS, btrfs), there are file access permission rules.
Hence if I mount a HDD which include a unix OS on it, when I access the file on this disk ...
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0answers
56 views
Per user priority of access to a file system
Please, let me know if there is a tool, which allows to give different reading (writing) priority to different users on Linux. I am looking for something similar to 'ionice' but able to set I/O ...
0
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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 ...
1
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1answer
980 views
How to change order to process priority on top command?
I have the below output from top command. Where is the process priority of the processes?
Mem: 678048K used, 336240K free, 0K shrd, 4K buff, 523012K cached
CPU: 0.5% usr 26.1% sys 0.0% nic 72.9% ...
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0answers
236 views
Suddenly I see a lot of involuntary context switches for multi threaded app
I have a multi-threaded app, with 4 worker threads that until recently performed very well on my 4-core CPU.
The system is running Ubuntu 16.04.3 LTS.
Today I updated my OS with sudo apt-get dist-...
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0answers
186 views
Prioritize UDP over FTP, SCP, etc. in Linux
I have a setup wherein one "master" Linux system communicates with 3 "slave" systems also running Linux on a dedicated Ethernet interface(just the master & the 3 slaves). The slaves send data to ...
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0answers
205 views
Does it make sense to combine chrt and nice?
I want a CPU-intensive process to have the lowest possible impact on other processes. I can use nice -19 for maximum niceness and chrt -i 0 to give the process a SCHED_IDLE priority.
Which is more ...
3
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1answer
912 views
Lower priority thread appears to block higher priority thread? [closed]
I have 2 threads, each set to a different real-time priority using SCHED_FIFO. Thread throttling has been disabled, so theoretically the highest priority thread should be able to use 100% of CPU ...
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0answers
139 views
macOS: nice/renice not working — no actual effect on cputime?
Although I can see a "nice" value ("NI") via ps, it seems to have no effect on the actual cpu-time used by a process:
PID %CPU PRI NI COMM
57081 77.6 12 10 cpu-chew
57080 77.1 12 0 cpu-chew
...
2
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1answer
176 views
lxc and sched_setscheduler
I am trying to run an application inside a Centos container and needs to run in real time. I googled around and the suggestion was to add lxc.cap.keep = sys_nice.
After I did it, lxc-start complains ...
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2answers
637 views
Assign a higher priority to a specific process by default
I would like to configure my desktop Linux system so that whenever I start running a specific programme (run that processes of this programme) the respective process gets assigned a high priority. How ...
1
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0answers
23 views
Keep an amount of ressources for virtual console (Ctrl + Alt + Fx)
Sometimes, a process on my computer uses a lot of RAM, and ends up using the SWAP. Therefore, my computer becomes extremely buggy, and I can't even toggle a terminal or a virtual console to kill the ...
8
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1answer
868 views
Does Linux Change a Process Niceness Automatically?
I know you can change a process niceness with setpriority or nice or renice.
However, does Linux automatically adjust/change a process niceness without user input?
I have a process for which I use ...
7
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3answers
3k views
Is changing the priority of a game's process to realtime bad for the CPU?
On Windows I have frequently changed the priority of a games process to 'high' or 'realtime' to get a performance boost. This has never resulted in any problems with my hardware. I was thinking that ...
0
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1answer
178 views
Exim dnslookup, priority and “blacklist” (not really blacklist)
I'm investigating how exim deliver mails, and I came to the conclusion that when the server is going to send a email exim makes a nslookup and get the higher priority (lower value) MX record and tries ...
4
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1answer
946 views
realtime pthread created from non-realtime thread with init.d
I have a piece of C++ code that runs just fine when I run it from a Linux terminal, but which throws an EPERM error when run from a SystemV (init.d) script on bootup. The error comes from a ...
0
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1answer
103 views
Why top doesn't list my application as real-time?
I am trying to learn the scheduling policy on Linux with a small C++ application. The same should be valid for C. I am changing the priority of my app using the code below:
sched_param tParam;
...
4
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1answer
747 views
SCHED_FIFO and SCHED_OTHER
I was trying to change linux process priority using chrt. I changed priority of one process to SCHED_FIFO from SCHED_OTHER. I could see some improvement in the perfomance. I run linux angstrom ...
7
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1answer
99 views
How does ionice work with multiple drives?
I understand how ionice can help you when you have multiple processes requesting access to the same disk resources, but how does it work when you have multiple disks?
For example, you have one rsync ...
0
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2answers
338 views
Job Priority in Batch Jobs
I do not have administrative privileges on the cluster that i am using. I'd like to prioritize some of the jobs that I have submitted. How do i incorporate that into my batch file:
#!/bin/bash
#$ -...
3
votes
1answer
717 views
How does Linux handle multiple processes?
I'm new to Linux technologies and bash scripting.
For now, I have a simple bash script that extract one subtitle track from a given MKV using mkvextract.
I was wondering: if multiple users were ...
0
votes
1answer
1k views
What is the difference between nice and renice?
What is the difference between the two commands nice and renice to manage process priority?
1
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0answers
54 views
getpriority returning different value on different hosts with same kernel version
I am running centos 6.6 on same type of hardware with kernel version "2.6.32-504.30.3.el6.x86_64"
Has anybody seen this why the below code when compiled and executed gives a different value on two ...
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2answers
995 views
What makes it possible for a `pulseaudio' process to get the nice level of -11?
I noticed that a pulseaudio process on my Gentoo Linux machine has the nice level of -11. But I don't know how it has gained such a high priority regardless of being owned by a normal user.
I know a ...
6
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1answer
4k views
How to sort ps output to find processes realtime priority and identify processess currently occupied running queue
How to properly identify real-time processes currently occupied CPU queue and count them using ps? I know there is a bunch of fileds like prio,rtprio,pri,nice but do not know correct to use. It seems ...
8
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0answers
469 views
User-based GPU priority
I have a computer running Linux (Kubuntu 14.04.3 LTS x64), where I use the CUDA toolkit to perform some computations on some Nvidia GPUs.
I share the computer with a few other users. How can I define ...
1
vote
1answer
208 views
problem with rsyslog filters
I have to make a rule in rsyslog.conf file in order to get the mail logs which at least notice priority but with exception of err priority to a certain path.
Here is the rule I tried to make for this:...
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2answers
2k 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
398 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 doesn'...
1
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1answer
248 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
...
3
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1answer
548 views
set default process and IO priority on Linux for given application/executable
Is it possible to set up some sort of default process and IO priority for given application/executable? I am thinking some sort of FS extended attribute or loadable "policy" of sort?
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2answers
232 views
What are some practical purposes for using renice? [closed]
I'm having a hard time finding a purposeful need for using renice more often, and I would like to know if there are any scenarios in which using process prioritization and adjusting it on-the-fly has ...
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3answers
15k views
Run linux process at very very low priority?
I have regular process that not so important but will consume so much CPU power, and I have another process which is really important, but it spend most of the time idle, but when it got a job it ...
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0answers
4k 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 timeslice,...
4
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2answers
2k 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 ...
4
votes
1answer
11k 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 ...
7
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1answer
5k views
How disk IO priority is related with process priority?
I'm running software that overloads disk IO sometimes. I don't need fast response from that software, I need fast response from other applications, so I could set low process priority for that. I want ...
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0answers
194 views
Why are the process priorities not respected?
I was running four jobs in the background with HTCondor. It sets the priority to 10. Then I was compiling something with make -j4 in the foreground (priority 0). However, the HTCondor jobs still got ...
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3answers
1k 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
4k views
What does a niceness value of (-) mean?
According to the man page, and wikipedia; nice ranges from -20 to 20.
Yet when I run the following command, I find some processes have a non numerical value such as (-). See the sixth column from ...
0
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1answer
85 views
software raid priority (systemtap)
I'd like to know on which priority software raid works (level 1 if it matters). So I wrote simple systemtap script to do the job, but I'm not sure if I have done it correctly.
[root@asus-ux21e ~]# ...
25
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3answers
15k views
Why can't I use renice to increase a process' nice value?
From man renice:
Users other than the super-user may only alter the priority of processes
they own, and can only monotonically increase their ``nice value'' (for
security reasons) within the ...
