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Questions tagged [cpu]

The CPU (Central Processing Unit), is the chip in the computer that actually performs the operations and calculations that are done as a program runs. It is essentially what executes a program.

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Find number of cores available in a given node

I need to fix the following piece of code. The code aims to determine the number of cores available in a given node. Step 1: Get the number of cores with TC=$(grep -c process /proc/cpuinfo) Step 2:...
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Launch a program to only specific resources

Question: How can I launch a program such that it only uses X ram and Y CPU cores, etc? I happen to be using Ubuntu in this case, but since I often am on other distros, I need a general GNU/Linux ...
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sensors reports negative CPU temperature for Ryzen

sensors used to work well for me but since upgrading to a Ryzen 2700X the readings don't make sense. nct6779-isa-0290 Adapter: ISA adapter Vcore: +0.56 V (min = +0.00 V, max = +1....
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1answer
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Find process source which executing python scripts [closed]

From last month some process is executing python scripts on my server with centos 6 with LAMP stack which are nothing but spam bots and eating server resources. Please check image below, How do I ...
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1answer
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What option argument can I give to `cpulimit -l` when I want a process to have unlimit cpu usage?

In cpulimit -l, --limit=N percentage of CPU allowed from 1 up. Usually 1 - 100, but can be higher on multi-core CPUs. (mandatory) What option argument can I give to -l when I want a process ...
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1answer
45 views

Linux + how to know which CPU Cores was active last day

recently , we upgrade our redhat server ( version 7 ) from 4 CPU CORE to 32 CPU CORE is it possible to know which CPU was triggered during last day ? I mean how to know if the additional CPU that we ...
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3answers
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Script - Cutting various lines and sort them

i want to sort the process of one user by the percentage of cpu used. I tried this ps aux|tr -s " "|cut -f3 -d " "| sort -| grep "user" > file name does this work?
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Mate panel keeps the CPU at 100%

I just upgraded the tumbleweed version and everything goes well so far, but a couple of days ago the mate session started to be unresponsive and the top and bottom panels freezes. I disabled the ...
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What's the point of “Scaling Governors” with Intel pstate?

Before Intel pstate, we had different scaling governors which used to change how the CPU frequency scales, but now, with pstate, we only have 2 "Governors": Powersave and Performance. We can also ...
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Script that displays information about most used processes

my script is `echo 'CPU:' | ps -eo pid,%cpu,pmem,vsz,time,command --sort=-%cpu | head -1` echo 'VSZ:' | ps -eo pid,%cpu,pmem,vsz,time,command --sort=-vsz | head -1 but I dont know how to write the ...
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Why both “/sys/devices/cpu” and “/sys/devices/system/cpu”?

Under /sys/devices, whys is there both /sys/devices/cpu and /sys/devices/system/cpu rather than just one or the other?
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How to check/monitor CPU power from command line?

I'm tasking with creating a GUI that models CPU power and frequency vs. time on a Linux OS. I know how to find the frequency of each core of my processor. I use cat /proc/cpuinfo. However, I can't ...
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online processor in nproc

When I run command $ nproc --all 4 DESCRIPTION Print the number of processing units available to the current process, which may be less than the number of online processors It ...
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33 views

Linux command which shows CPU scheduling

Linux command which shows CPU scheduling For example consider I have 1 CPU with 2 treads and 10 process are running Is there a command which can show CPU scheduling where we can see which process ...
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CPU thermal throttle counters

In each CPU device directory (/sys/devices/system/cpu/cpu*) there is a directory called thermal_throttle that contains two counters called: core_throttle_count package_throttle_count What are the ...
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How to force all processes with a known name D, started from a given process K have equal CPU ticks scheduled?

Say we have a process K that in itself starts docker images D. We want to make sure that CPU ticks are provided to each and every one from that pool of processes D in a round-robin, or fair meaning ...
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Overheating while running Linux in Laptop

I've been running into issues while running Linux Mint MATE 19 64-bit in my laptop (Toshiba L750). It's installed in a SSD drive and there are 16GB of RAM installed. I purchased a SSD to move to ...
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1answer
136 views

Why is only Linux affected by the Bay Trail cstate bug?

I recently tried to install Linux (I tried Ubuntu and Arch) on a system using a Pentium N3510 (Bay Trail) processor and initially failed with random hangs and sluggishness. Trying out various things, ...
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1answer
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lscpu shows incorrect number of cpus [closed]

I've just checked cpu informations on one of ours servers and I am a little bit confused. Intel says that this model has 28 cores, whereas lscpu shows only 2. Am I missing something? Virtualization? ...
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1answer
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Kernel module shows me 8 processors instead of 4 for Intel i5-2500K

My question mostly about hardware, specifically the Intel i5-2500K CPU which Intel describes as having # of Cores 4 # of Threads 4 Linux shows me 4 processors: $ cat /proc/cpuinfo | grep ^...
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1answer
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Why does cpuinfo show only 2 processors? [duplicate]

I'm running the following command: cat /proc/cpuinfo | /bin/egrep 'processor|model name|cache size|core|sibling|physical' Which gives this output: processor : 0 model name : Intel(R) Xeon(R) CPU ...
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1answer
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What exactly does “Illegal instruction (core dumped)” mean? [duplicate]

I see a lot of solutions to resolving the problem exemplified by Illegal instruction (core dumped) But, I'm wondering what exactly that means? What generates that error, and what's the root cause ...
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systemd-udev high CPU usage

I just upgraded Linux Mint from 18.3 to 19, and I am having very high cpu usage from systemd-udevd top - 14:00:58 up 14:12, 1 user, load average: 3.95, 3.37, 3.02 Tasks: 241 total, 2 running, 169 ...
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2answers
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Actual compilation differences between CPUs

For a project I intend to compile various *NIX OSs and their relative packages with different CPUs in order to maximize optimization and performance for specific systems. In order to save time and ...
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1answer
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cgroups: Is it possible to limit cpu usage by process name instead of by pid

As we know, cgroups can limit cpu usage of processes. Here is an example: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 30142 root 20 0 104m 2520 1024 R 99.7 ...
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1answer
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Understanding output of lscpu

You can see the output from lscpu command - jack@042:~$ lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 56 On-...
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2answers
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How to calculate the number of vcores on a Linux machine

In my Linux machine I have 32 vcores. And from lscpu, I can see same. For my CPU, "Thread(s) per core" is 2. So does it mean that I have actually 64 vcores?
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Intel Pstate frequency limits are overridden

Problem : Run all core on minimum CPU frequency on Intel pstate driver on ubuntu 14. cpupower frequency-set --governor performance --max 1300MHz I am trying to run my cpu cores on different ...
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1answer
395 views

Change the cpufreq driver from intel pstate to acpi

I am trying to disable the intel pstate cpufreq driver and replace it with acpi to get maximum cpu control. I tried this. vim /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=disable quiet ...
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0answers
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Scale down to a specific frequency on Ubuntu Linux 14 w/ Intel CPU

I am trying to scale down one of the CPU frequencies. I am using Ubuntu 14 and Linux kernel 4.4. I want to scale down the cpu3 frequency to 1.2 CONSTANT (no throttle). Things I have tried: I want ...
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3answers
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What does “m” mean in mpstat?

I check the manual of mpstat it states: The mpstat command writes to standard output activities for each available processor, processor 0 being the first one. Global average activities ...
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1answer
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What is CPU min MHz in lscpu output?

There are CPU MHz, CPU max MHz and CPU min MHz in lscpu output. What are they mean? Especially the CPU min MHz? We can think CPU max MHz is maximum CPU frequency and CPU MHz as current usage. Why ...
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Not all CPUs entered broadcast exception handler Kernel Error

I've been dual booting Ubuntu on my laptop and for a few months its been perfect. Today however when booting up this error has appeared, and despite numerous restarts nothing has resolved it: Kernel ...
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1answer
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Rolling back Intel-microcode updates and computer speed

I assume that Debian package intel-microcode packages gradually correct the various spectre and meltdown issues. From what I understand about these problems, the only way to correct them on existing ...
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1answer
529 views

How is runq-sz counted in sar?

I would like to ask question about the output from sar -q . I appreciate if someone can help me out with understanding runq-sz. I have a system which cpu threads are 8 cpu threads on RHEL 7.2 . [...
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1answer
832 views

What Linux kernel version(s) have a fix for the L1TF (Foreshadow) exploit?

Foreshadow is a new speculative execution exploit targeting Intel's SGX on Core chips What Linux kernel version(s) contain a fix for the L1TF exploit?
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2answers
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Run factor in parallel

how to run Linux's factor in parallel, i.e. utilize all CPU cores? I have tried to run factor <prime number> but unfortunately only one CPU core is being utilized.
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1answer
33 views

How does ps measure %CPU per process (and can this be changed?)

When doing ps -r -e -o pcpu=,comm=, the % CPU displayed per process, over how long time is this value measured? Is it one second? The manual page does not seem to mention this. And a follow-up ...
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1answer
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How to set the cpu frequency to the max on SLES12?

I tried: cpupower frequency-set -g performance But still, the frequency is only at 1200 MHz. It only goes up if I put a load on the machine, but it should be running at always 100% cpu frequency. ...
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497 views

Find out exact cause of a process' high CPU usage (gnome-shell)

This question might be specific to gnome-shell, which is constantly using 60-80% CPU on my system. (4.1GHz CPU frequency, arch linux, up-to-date software) How can I find out what exactly is the cause ...
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1answer
112 views

What does cross-socket traffic mean?

When reading this Kubernetes blog post about Intel's CPU manager it mentions that you can avoid cross-socket traffic by having CPUs allocated on the socket near to the bus which connects to an ...
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1answer
108 views

Single CPU 100% by lspci

On Fedora, the lspci command keeps staying at ~100% while I'm not doing anything with my computer. I've done a clean install last week and before that I also had this problem. Top output gives me: ...
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100C CPU temperature in Ubuntu's “sensors”, but 39C in BIOS, which one is correct?

I have MSI x470 gaming motherboard and AMD Ryzen 2600x and running Ubuntu 18.04. The issue is, when I type sensors in the terminal it gives me output on CPU temperature to be 90-108° C (only ...
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2answers
3k views

What does the “bugs” section of /proc/cpuinfo actually show?

On a Debian Stretch and testing/Buster system with a current kernel and installed microcode I still see meltdown and spectre listed as bugs in /proc/cpuinfo. However, running the spectre-meltdown-...
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3answers
3k views

Why are some Intel family 6 CPU models (Core 2, Pentium M) not supported by intel_idle?

I've been tuning my Linux kernel for Intel Core 2 Quad (Yorkfield) processors, and I noticed the following messages from dmesg: [ 0.019526] cpuidle: using governor menu [ 0.531691] clocksource: ...
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2answers
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Identify and remove noisy software [closed]

When I open up my session, my laptop speakers start whining. This does not happen when I use the guest user session. The noise stops when there is CPU activity (for eg. moving mouse, starting program,...
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0answers
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Linux - Why are my core IDs not consistent? [duplicate]

I'm currently looking at a system where I don't understand how the core IDs are assigned by the Linux kernel. Some info on the system - @mySystem~]$ lscpu Architecture: x86_64 CPU op-mode(s): 32-...
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1answer
177 views

Centos - top takes 100% cpu

I have a CentOS server where I'm running the top command, I can see that the process top utilize 100% CPU. Can anyone assist on how to investigate/solve?
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2answers
159 views

Memory Per Core [closed]

I am using the super computers in the network provided by Compute Canada and in the documentation page I see the following: I am quite curious - what is the concept of memory per core here? I thought ...
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Can I stop boinc while I watch a video?

I like to watch videos form https://areena.yle.fi/tv . Sometimes my computer seems to be too slow for watching because I have boinc running. Is there a way to write a script such that if I start to ...