Questions tagged [priority]

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How to tune BFQ schduler to prevent a single low priority process from severely degrading system performance?

I have been trying to use nice/ionice for a while and it turns out that bfq ignores ionice parameters. So how do I prevent a low priority process from consuming all the io bandwith to the detriment of ...
Morrison's user avatar
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23 views

dhcpcd: set priority for link-local connections

I see that there is a metric keyword in the dhcpcd.conf (as explained e.g. https://unix.stackexchange.com/a/413036/47009), which allows me to set the routing priority for a given interface. However, i ...
umläute's user avatar
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2 answers
79 views

How to find PID of all processes related to a given process?

How can I go about finding the PID or other information about a process that is doing the work of another process? I'm talking about kworker threads, for example, or any other threads/processes that ...
stochasticlover1's user avatar
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76 views

Linux: Do userland threads have a higher priority when performing system calls?

From what I understand, Linux features kernel preemption, meaning that a thread executing a system call can be preempted and rescheduled to run on the next epoch. This leads me to wonder if a thread ...
exliontamer's user avatar
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55 views

Creating a priority wifi list in connman

I'm using connman to manage my network connectivity on an embedded device (Beagle Bone Green Wireless). I've been able to connect to networks and save those networks for future use but I'm having ...
Fabio's user avatar
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150 views

Is there any way to achieve prioritized IO operations in Linux 5.xx?

I run a lot of long-lived and io-heavy processes in addition to interactive processes on my machine. Unfortunately, they slow the interactive operations down to a crawl despite my best efforts. I ...
ATLief's user avatar
  • 290
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1 answer
691 views

Changing CPU affinity on they fly has no result

so I am creating my own script to set priority and cpu affinity for important processes on my system, and I tried using taskset command, but it seems to do nothing. Here's sample: import psutil import ...
Dolidod Teethtard's user avatar
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0 answers
163 views

How can I make my game's FPS be virtually unaffected by a low priority background task?

I'm running a desktop system where I often have long-running compilation tasks in the background. I'd like to play CPU-limited games while they're running without a significant drop in FPS (the game ...
Atemu's user avatar
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3 votes
0 answers
160 views

How do I flag a process to avoid hyperthreading (SMT)?

Suppose I have an 18 core CPU with SMT enabled, and there are 18 long runnning processes, all using ~100% of a thread. If I start a 19th process, the kernel will schedule it to run on one of the cores,...
uLoop's user avatar
  • 141
1 vote
1 answer
1k views

nftables table and chain priority

I have a problem with my nftables setup. I have two tables, each one has a chain with the same hook but a different name and priority. The tables are in different files which are loaded by an include ...
smhrambo's user avatar
1 vote
0 answers
149 views

does pthread_setschedparam can change the priority on the fly once the thread is running? how can I change the thread priority for a running thread

I want to change a thread priority and I have found many examples using pthread_setschedparam, but I need to confirm if the priority can be changed on the fly if the thread is already running. In the ...
alejandro mendoza's user avatar
1 vote
0 answers
304 views

Netplan: give IPv6 priority over IPv4

On a dual-stack workstation (single interface, Ubuntu 18.04), I'd like IPv6 to be chosen first, before IPv4. I guess that means essentially to have domains being resolved first by DNS6, and then by ...
Déjà vu's user avatar
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2 votes
0 answers
169 views

Slurm multifactor priority - how to configure Slurm to consider past usage?

I'm trying to configure our Slurm to allocate users' jobs according to past usage. The goal is to have the job priority consider past time usage of mainly GPUs. I understand I must use the FairShare ...
itay1itzhak's user avatar
0 votes
1 answer
132 views

in what situations will ni% in top is not 0

I learnt that ni represents the cpu used for userspace processes whose niceness or priority value is changed, but in my system, which is CentOS Linux release 7.9.2009 (Core), I did below test, all the ...
russelc's user avatar
0 votes
1 answer
511 views

Give user permission to change priority of an IRQ/root process

Is it possible, in Linux, to allow an user to change the priority of a process owned by root? More specifically an IRQ process? For an embedded real-time application I want to raise the priority of ...
fws's user avatar
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4 votes
1 answer
20k views

What is swap priority and why does it matter

While seeing the manual for swapon command the priorty option is described as -p, --priority priority Specify the priority of the swap device. priority is a value ...
Sudip Ghimire's user avatar
4 votes
2 answers
985 views

How is process priority calculated?

Can someone explain how "real" process priority (i.e. pri_baz field of ps) is calculated? My guess is: pri_baz = 99 - static_priority # if static_priority > 0 (real-time process) pri_baz = 100 + ...
Jorge Lopez's user avatar
2 votes
0 answers
766 views

Is pulseaudio's default nice value (-11) actually ineffective due to autogroup?

The pulseaudio daemon runs with nice level -11 by default, via rtkit. However, I'm noticing choppy audio at times of high cpu load, and decreasing the nice value even further by setting high-priority ...
Marc.2377's user avatar
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1 vote
1 answer
118 views

There is a high priority keys combination for the opening terminal in Linux if UI is hanging on?

Several times I've run into with the problem of Ubuntu hanging when a memory leak happens in some application process (Chrome/Sublime/etc.). As a result, the keyboard and mouse stop reacting. I even ...
Oleksandr Bratashov's user avatar
0 votes
1 answer
488 views

Is it possible to give a program priority without running as root?

I want to give a program I'm running in linux priority over other programs. I have sudo access and tried using sudo and the nice command. Specifically I ran a bash script file called RUN.sh that has ...
user378159's user avatar
1 vote
1 answer
335 views

How to prioritize packages installed from files in APT?

I want to have packages installed manually via dpkg -i not being updated. I figured the most elegant way to do this would to pin them to a high priority. The manpage of apt_preferences says Assign ...
philipp2100's user avatar
1 vote
1 answer
1k views

SCHED_RR and SCHED_FIFO only work on "prempt kernal"?

I am running a python program on the raspberry Pi (Raspbian) that I would like to give higher priority. I want to run the following command : $ sudo chrt --rr 50 python3 loopExample.py I have read ...
Lightsout's user avatar
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0 answers
42 views

Why a long type memory is reserved to nice value in the PCB in Linux?

All right, my question is not sufficiently specific. I've not mentioned the kernel version, the distribution and other potentially interesting things. But, anyway... these are important but doesn't ...
Daniel Bandeira's user avatar
1 vote
1 answer
344 views

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?
Juan Miguel Ruiz-Olivares's user avatar
2 votes
1 answer
1k 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 ...
Luigi Capogrosso's user avatar
1 vote
1 answer
322 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/...
Mikola Akbal's user avatar
2 votes
1 answer
725 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 ...
explorest's user avatar
  • 552
2 votes
0 answers
48 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. ...
HCSF's user avatar
  • 213
0 votes
1 answer
2k 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 ...
danglingpointer's user avatar
1 vote
1 answer
59 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 ...
pah8J's user avatar
  • 227
1 vote
0 answers
160 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 ...
S.V's user avatar
  • 121
1 vote
1 answer
8k 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 ...
galex-713's user avatar
  • 215
2 votes
1 answer
3k 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% ...
Ravi's user avatar
  • 749
2 votes
0 answers
795 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-...
Bram's user avatar
  • 869
1 vote
0 answers
530 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 ...
John Smith's user avatar
2 votes
0 answers
702 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 ...
kontextify's user avatar
4 votes
1 answer
2k 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 ...
Echo404's user avatar
  • 113
3 votes
0 answers
419 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 ...
not-just-yeti's user avatar
2 votes
1 answer
461 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 ...
msbic's user avatar
  • 21
7 votes
2 answers
3k 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 program (run that processes of this program) the respective process gets assigned a high priority. How to ...
ingli's user avatar
  • 1,725
1 vote
0 answers
26 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 ...
Sidahmed's user avatar
  • 1,308
8 votes
1 answer
2k 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 ...
Luis's user avatar
  • 133
9 votes
3 answers
7k 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 ...
Totem's user avatar
  • 1,101
0 votes
1 answer
346 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 ...
Mc Kernel's user avatar
  • 521
4 votes
1 answer
2k 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 ...
codemonkey851232's user avatar
0 votes
1 answer
239 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; ...
Ali's user avatar
  • 171
4 votes
1 answer
2k 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 ...
Gilson Varghese's user avatar
7 votes
1 answer
298 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 ...
user159726's user avatar
-1 votes
2 answers
884 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 #$ -...
user147813's user avatar
3 votes
1 answer
2k 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 ...
Crescendolls's user avatar