Questions tagged [priority]
The priority tag has no summary.
92 questions
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Is there any advantage to changing process priorities using a kernel module instead of nice / chrt?
I'm working on a project where I want to study the impact of process priority on system behavior.
I know that tools like nice, renice, and chrt can change the priority or scheduling policy (e.g., ...
0
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1
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126
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Why does no packet traverse the nat chain in the output or postrouting hook with this ruleset?
I have a machine with the network interface enp0s3 which is assigned the IPv4 address 192.168.20.254. Furthermore, on another machine there is a DNS server listening on the IPv4 address 192.168.20.10. ...
- 3,951
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1
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830
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Set highest CPU and IO priority for a systemd service
How to set CPU and IO priority for a systemd service? In partucular, how to set the highest values?
(Assume that the service is idling most of the time and will absolutely NOT clog the rest of the ...
- 1,569
4
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2
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4k
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nftables priority filter: what does this mean?
The nftables wiki explains the priorities here. Clearly, the priority is a numeric value like -10, 0 or 10. The Red Hat nftables documentation does the same.
Priorities remain numeric in the examples ...
- 93
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When/where to set network bond (active-backup) interface priorities on boot?
This is a follow-up to linux bonding active-backup mode set priority for multiple interfaces? I'm too new to post a comment there.
I've confirmed that ip link set dev <x> type bond_slave prio &...
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632
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How to set default metric on IPv6 route received by RA message
I have two ipv6 interfaces(eth1 and eth2), that receives an IP via DHCP(dhclient is used), but the routes are received via RA messages from switch, to which these interfaces are connected. Since RA ...
2
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1
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169
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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 ...
- 21
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260
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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 ...
- 6,734
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469
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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 ...
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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 ...
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310
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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 ...
- 886
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354
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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,...
- 141
2
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2
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3k
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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 ...
- 23
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267
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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 ...
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416
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 ...
- 656
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330
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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 ...
- 21
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1
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239
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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 ...
- 3
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1
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998
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 ...
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7
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1
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33k
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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
...
- 309
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2
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1k
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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 + ...
- 119
2
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0
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945
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 ...
- 1,202
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154
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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 ...
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1
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652
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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 ...
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1
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640
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 [...
- 337
1
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1
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1k
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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 ...
- 165
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0
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55
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 ...
- 152
1
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1
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490
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?
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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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1
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406
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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/...
- 11
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1
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857
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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 ...
- 552
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54
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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.
...
- 223
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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 ...
- 209
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82
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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 ...
- 237
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206
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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 ...
- 141
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9k
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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 ...
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1
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4k
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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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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-...
- 999
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0
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600
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 ...
- 11
3
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1
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879
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 ...
- 181
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2k
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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 ...
- 123
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0
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457
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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
...
- 151
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1
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528
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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 ...
- 21
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2
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4k
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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 ...
- 2,039
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0
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39
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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 ...
- 1,368
8
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1
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2k
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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 ...
- 133
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7k
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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 ...
- 1,171
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427
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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 ...
- 531
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1
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2k
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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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1
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346
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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;
...
- 181
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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 ...
