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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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Why is Linux in ChromeOS Flex reporting wrong number of CPU sockets?

dajnyx@penguin:~$ lscpu ... CPU(s): 2 On-line CPU(s) list: 0,1 Vendor ID: GenuineIntel Model name: Intel(R) Celeron(R) CPU 1037U @ 1.80GHz CPU ...
Wolk's user avatar
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How to see what statement (memory address) my program is currently running: the program counter register, through Linux commands?

For a reason I need to find, a C++ application looks being stuck in a docker container. I did a docker exec -it a_template_cpp bash and entered into it. I know the top and pmap commands, and also that ...
Marc Le Bihan's user avatar
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2 answers
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Why are my benchmark times not repeatable, even for a CPU-bound task?

I'm running some benchmarks on my Linux desktop/laptop computer, but I'm not getting reliable results. I'm running a CPU-intensive task that does negligible I/O and doesn't use much RAM. My computer ...
Gilles 'SO- stop being evil''s user avatar
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CPU running well under maximum frequency

I use my computer for very CPU intense simulations, but no matter what I do the actual CPU frequency wont ever come close to hardware capacity. I have an i9-13900K, which maximum CPU freq. is 5.8GHz. ...
aleferna's user avatar
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slurm - minimizing effect of offline CPUs

I am doing experiments seeing how slurm behaves when it finds offline CPUs. In my experiments, slurm provides configurations that make available too few CPUs. Here's a few examples from an 8-cpu node ...
eftshift0's user avatar
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Intel turbo boost all core clock speed in practice

My understanding is that Intel's quoted "max turbo boost" speed is only guaranteed when a single core is active, and that when all cores are active, the clock speed could conceivably fall to ...
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irq/9-acpi process using 27% cpu

I see this process constantly using 20+% cpu PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 129 root -51 0 0 0 0 S 27.2 0.0 9,04 [irq/9-acpi] ...
user3329064's user avatar
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Base clock (frequency) setting is required in Ubuntu 20.04

I'm currently using ubuntu 20.04 on an HPE DL380 Gen10 server. The CPU is using Xeon 4216. The problem is that the CPU in question has a base clock of 2.1GHz. When checking with Turbostat or cat /proc/...
pal pay's user avatar
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How to isolate cpu cores, even from kernel space, at boot?

I have a faulty Ryzen 5900X desktop CPU. Previously, I somewhat tamed its faulty cores via isolcpus=2,3,14,15 kernel parameter in GRUB2 (see https://blog.cbugk.com/post/ryzen-5850x/). However, on ...
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cpuset is turned on, /sys/fs/cgroup/cpuset/cpuset.cpus is not found

My cpuset controller is enabled, but I don't find the corresponding file, I want to know why, any help is greatly appreciated ^_^ OS ┌──[[email protected]]-[~] └─$hostnamectl Static hostname: ...
山河以无恙's user avatar
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lm-sensors, CPU sensors not detected

I have a fresh install of Manjaro running on a server i have built. I have an AMD Genoa 9334 ES. On windows I can detect the correct core temperature (see attached images). On the linux OS (Ubuntu 24....
Nan Rait's user avatar
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148 views

How to *actually* limit CPU usage for Hashcat

I’d rather not fry the living crap out of my CPU. The hashcat program uses a lot of CPU and GPU. I know, the simple solutions people recommend online, such as using tools to limit cpu usage, such as ...
security_paranoid's user avatar
2 votes
1 answer
46 views

How to disable logical processors in OpenBSD?

It is well known that OpenBSD disables hyper-threading by default. However, htop shows 16 CPUs: 8 online and 8 offline, which takes extra space on the screen and is not very informative. Moreover, ...
nalzok's user avatar
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Debugging RCU stalls on Ubuntu Server 22.04, 5.15-realtime

I am trying to isolate CPUs on an AMD EPYC 8534PN (64C/128T). Unfortunately, I see the RCU stalls and the server crashes over and over. And I am not really sure what I am doing wrong. The crashes only ...
ninjab3s's user avatar
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How to disable Processor Performance Boost Mode in PopOS (Or similar distros)

So in Windows 10, I have to edit the registry to make this option available so I can disable it. Why do I need to do this? Because the processor will boost beyond the total power output of my laptop's ...
The Gray Jedi's user avatar
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How could one create a hash fingerprint for a computer's architecture/instruction set?

Imagine a protocol where participants sign a schema document to declare which version they will follow. To define functions used in the protocol, without recourse to URLs, we could define operating ...
Lee's user avatar
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How to work with CPU and memory intensive application in Linux?

This is the scenario,- it is a Java Application mainly, Heap Dump & Thread Dump is not helping me. Maybe I am not wise analyzing it. Observation 1) Lots of memory seems to be utilized. [maddipp1@...
Dev Anand Sadasivam's user avatar
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Avoiding the need for reboots when CPU thermally throttles itself

I'm on a Dell laptop with Sandy Bridge Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz CPU running a 5.15.0-100-generic Linux kernel. The CPU goes up to 3.4GHz (as both the MATE CPU Frequency Monitor ...
Petr Skocik's user avatar
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Manually Assigning C-states to CPUs for Energy Optimization

Is it possible to manually set specific C-states for CPUs, similar to how we select processor frequencies, for energy optimization purposes? I'm interested in tools or methods that allow such granular ...
sako's user avatar
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Device keeps crashing with 100% CPU usage

From time to time my Laptop freezes and is unusable with 100% CPU usage on at least 1 core. I left btop open but the freeze seemed to be happening too quick as the process with the highest processor ...
Displayname's user avatar
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Android 12 and 14 GPUWatch missing

I am doing some generic testing for performance for Android 12-14 with our work build / devices. On two of the devices (XCover5 and Active Tab5 Pro running Android 13 and 14 respectively) i have ...
MOLEDesign's user avatar
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2 answers
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Using thermald for cpu to stop overheating

Sometimes, my laptop with Intel Core i3 is overheating. For example today. $ sensors radeon-pci-0300 Adapter: PCI adapter temp1: +59.0°C (crit = +120.0°C, hyst = +90.0°C) coretemp-isa-0000 ...
xralf's user avatar
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A simple memcpy loop with stride of 8-16-32 Bytes, no L1 cache misses, what stalls backend cycles?

I am trying to understand the CPU cache performance in a single producer single consumer queue algorithm, but cannot pinpoint the cause of performance degradation in some cases. The following ...
xealits's user avatar
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1 vote
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Curious lscpu Output Related to CPU Calculation

I have been trying to understand lscpu's output and came across several threads dedicated to concepts of CPUs, physical cores, and threads. Based on those threads, to get the total number of CPUs (...
Jason's user avatar
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3 votes
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Can there be a case while /proc/cpuinfo file has several different model & model name fields?

I want to create script gathering CPU info from the server. At the certain server output of file named in question title has 12 model and model name fields which are equally to each other. These case ...
palmasd1's user avatar
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Getting CPU temp from the command line

What is the best way to get the CPU temperature on Linux from the command line? On one small portable system, I was able to get the CPU temperature from here: /sys/class/thermal/thermal_zone0/temp or ...
ppppppp2's user avatar
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"MDS CPU bug present and SMT on" Bugs decteted after running JURNALCTL on opensuse leap 15.5 shell

Running JURNALCTL on opensuse leap 15.5 shell , it detected the following bugs: 1- MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/...
Harlequin's user avatar
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cset shield fails to execute task on a shielded core

I'm trying to run a benchmark on a shielded core on x86-64 (4 cores) and Ubuntu 22.04. Shielding core 3 runs fine: paul@cube-ubuntu-22:~/simd-agner/build$ sudo cset shield -c 3 cset: --> activating ...
Paul Jurczak's user avatar
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Boosting specific cpu core (first one) and keep others at level so that first thread reach maximum frequency

I have Ubuntu 22.04 running on amd epyc 7443p cpu 24 cores / 48 threads. I need to run first core (zero) at maximum boost frequency that hardware allows, or at least higher than all others. I have ...
user10685787's user avatar
-1 votes
1 answer
116 views

How can I find the human readable name for a CPU? [duplicate]

I need to know the name of the CPU used in a GKE cluster I have launched. The gcloud command has a --min-cpu-platform option, but my understanding is that is the minimum and I may get a later CPU ...
Haywood Slap's user avatar
1 vote
0 answers
186 views

How to reduce power consumption of old laptop turned into linux server

I'd like to turn some an old laptop into a linux server and reduce consumption while idle. I've installed xubuntu and it works perfectly. I've already check the BIOS and there is no WakeOnLan or Boot ...
Oscar's user avatar
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Understanding CPU threads is used by a multithread application

Recently, I did some research on how the CPU core is used by a multi-threaded application. I can see what cores each thread is using by using the following command: For example: ceph-osd is a multi-...
huynp's user avatar
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Switching from intel to amd without reinstalling software, is it possible?

I'm soon going to be upgrading my hardware and I'm planning on switching to an AMD processor. As I have plenty of stuff I'd really like to avoid having to reinstall my software, so I'm planning to ...
php_nub_qq's user avatar
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1 answer
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How should Load Average be calculated on a CPU with Efficiency Cores?

I recently received a MacBook Pro with an M1 pro CPU, which has 2 "efficiency" cores and 8 performance cores. When I run htop/btop/top I get a load average of >2 because the process ...
acjca2's user avatar
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Is the information read in /proc/*pid*/stat updated by a timer interrupt?

As documented in https://www.kernel.org/doc/Documentation/cpu-load.txt the information in the pseudo file /proc/stat is updated by a timer interrupt, which means that /proc/stat may not give a ...
POtaoPereiraRosen's user avatar
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Why is it possible that the combined processes CPU usage is higher than the total CPU usage, as reported by top? [duplicate]

When I check top, with a delay of 0.5 seconds, sometimes the total CPU state percentage is lower than the sum of the CPU usage of individual processes. Here is an example, where that is observed: top -...
POtaoPereiraRosen's user avatar
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Cannot switch offline a specific CPU

I am trying to switch some CPU in my system by echo "0" > /sys/devices/system/cpu/cpuN/online. cpuN indicates to a specific CPU number. My system have 48 CPUs and I successfully switched ...
VincentHuang's user avatar
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0 answers
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Looking for a TUI that can visualize CPU/RAM usage data captured by atop

I've seed s-tui, and it is lovely, but is there something similar that can display usage data that was already captured into files? I'm using atop to generate these files. If needed I'll switch to ...
user2761064's user avatar
0 votes
2 answers
791 views

Restrict all already running processes to a range of CPU cores

I've got an AMD 7950X3D CPU which has 32 total logical cores, 16 of which (0-15) have access to extra cache. To optimize my system for gaming while multitasking I want to run Steam and all the ...
Dmitri Ranfft's user avatar
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CPU Operational Load on WSL slows down entire computer

I'm running a Dell XPS15 with 64 GB Ram and a i7-12700H (6 performance cores, 8 efficency cores). I just recently (read: 2 weeks ago) did a clean upgrade and reinstall to Windows 11 with all up-to-...
Joe's user avatar
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raspberry pi specific script to run commands upon cpu reaching defined temperature

i just need certain commands (that control fans and light up a warning LED) to be run when cpu temperature exceeds a certain threshold and other scripts if and when they finally return to below ...
Robert Cotterman's user avatar
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1 answer
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CPU IDLE low as results of bad disks is it the case here

Low CPU IDLE can be caused by a variety of factors, including:Insufficient RAM or slow Hard Disk Drive but in our RHEL server RAM memory have enough RAM but from dmesg we found couple errors about the ...
yael's user avatar
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Cumulative CPU time across reboots

How can I record and view cumulative CPU time on system across reboots? Essentially, it should be like the TIME+ column of top, but not per process. In other words, like vnstat, but for CPU time. I am ...
wjwrpoyob's user avatar
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0 answers
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What does QNX's top CPU idle percentage really means?

I am using QNX (ARM Cortex A53 with FOUR cores) and when I do top, I have the below. According to the below idle percentages for each of the core, I'd like to confirm CPU/Core 0 is the most idle, ...
unebonnevie's user avatar
1 vote
2 answers
5k views

Are Intel or AMD processors generally regarded as "better" for Linux [closed]

Are there any differences between Intel and AMD processors in how Linux runs? Specifically in terms of performance, optimizations, and driver support? To simplify things, I am just talking about the ...
Luke's user avatar
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CPUIdle: what could be the reason for a core refusing entering the C6 state though the kernel requests so?

I'm trying to measure the time that a core spent in each c-state during a workload run and found a weird phenomenon: the kernel requests a core to enter C6, but the hardware only stays in C1. The ...
stunly45711's user avatar
-1 votes
1 answer
106 views

Why cpu number is limited?

seeing this log: APIC: NR_CPUS/possible_cpus limit of 64 reached. but I didn't set any limitation on CPU number.
Mark K's user avatar
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Unable to find any information about TLB on my computer or obtain information about hardware counters about TLB

The Ubuntu version I am using is Ubuntu 18.04.6 LTS, and the kernel version is 5.4.0-148 generic. My processor is 12th Gen Intel (R) Core (TM) i7-12700. I would like to know the number of TLB ...
citrusyi's user avatar
0 votes
1 answer
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In a computer with two CPUs, how can I get the physical address of local memory of each CPU?

My computer has the following specifications 2 Intel CPU x86_64 Total 8GB memory (4GB per CPU) O/S is Rocky Linux 9 I want to reserve 1GB of memory per CPU using the memmap parameter in grub. I ...
raon0ms's user avatar
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0 votes
1 answer
106 views

"Hello world" to pixels -- everything between OS, driver, and hardware (CPU, GPU, PCIe, USB-C to display)

Can someone explain "Hello World!" in relation to the modern stack of software and hardware on a modern Linux or Unix machine? Doing a $ strace on the binary generated by following ...
codepoet's user avatar
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