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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Cannot achieve maximum CPU frequency with Intel_Pstate Driver - RHEL 7.7

I'm struggling with intel_pstate performance governor not running at max CPU speed. I have a 2.2ghz system, and it needs to be running at full speed for valid reasons. # grep -E '^model name|^cpu MHz'...
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What does cause such high CPU fan speeds?

So, everything worked fine yesterday. Today, my CPU fan seems upset. It alternatively goes up to a high speed of around 5000 rpm, then back down to a low speed of around 2300 rpm, and up again, in ...
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Cpufreq doesn't quite want to set my CPU frequency permanently

I'm on debian using the package cpufreq. I have the userspace governor loaded and it works to apply it. I have used intel_pstate=disabled in my kernel line because otherwise userspace isn't possible ...
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Bind 9 process of named is using one core cpu only

i Have a DNS server running on Debian os , the named process is taking 394% of cpu. i noticed it is using one core of the 1 cores provided to the whole VM . top - 17:29:04 up 105 days, 1:33, 1 user, ...
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How does Linux detect number of “possible” CPUs

I have an AMD CPU with 8 cores and 2 threads per core. Linux (correctly) shows this as 16 "cpus". However, sysfs actually shows 32 "possible" cpus, with 16 of them not present and ...
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AMD 3970x Threadripper - box *seems* to slow down after some heavy work

I'm not sure yet if this is my imagination yet (Nor do I know the most straightforward way to figure it out), but I have an AMD 3970x 32 core 64-thread "ThreadRipper" CPU (MSI Creator TRX4 ...
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Syntax for number of cores in a Sun Grid Engine job file

I want to use the HPC of my university to qsub an array job of 3 tasks. Each task runs a Matlab code which uses a solver (MOSEK) that exploits multiple threads to solve an optimization problem. A ...
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How to find out on which core a thread is running on?

Let's say we have a CPU-intensive application called multi-threaded-application.out that is running on top of Ubuntu with a PID of 10000. It has 4 threads with tid 10001, 10002, 10003, and 10004. I ...
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How to get number of threads/tasks per core in Linux?

As you may know, in Linux, each CPU core has its own run queue. How can I get the number of threads currently running on each core in Linux (Ubuntu)?
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/sys/devices/system/cpu/cpufreq/policy* missing for cores above 24

i am tweaking cpu setting to get reliable benchmarks on AMD Ryzen 9 3950X cpu with 16 physical cores and 32 logical but the virtual directory in /sys/devices/system/cpu/cpufreq/policy* and the ...
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Stop specific processes from heating up my system's CPU

I have a process doing some computation the whole time. It causes my system's CPU to heat up and the fan to spin faster. I want this process to run, but with a low priority. I don't want my system to ...
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Processor is slower after switching from AC to battery and back

I've noticed that my system slows down after switching to battery, but doesn't speed up once it's plugged in again. For example, if I run a portion of an R script after booting, it finishes in ~25 ...
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Does a process filling all logical cores have a negative impact on performance? [closed]

Because of hyper-threading, my CPU has 2 logical processors per core. If I understand the premise of hyper-threading correctly, it allows each core to have a separate cache and instruction pointer for ...
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How do I stop wget from causing CPU soft lockup?

When I run wget on a long download, I get a CPU soft lockup (shown in logs) after a few hundred MB. Everything freezes except for the tty output (if I already had switched to it), and magic sysrq keys....
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“core temperature above threshold, CPU clock throttled” causing laptop to freeze intermittently on Ubuntu 20.04

I have a Dell G7 15 7590 laptop. I recently installed Ubuntu 20.04. Now one to two times a day the computer freezes. Sometimes it comes back and sometimes I think a full restart is required. cat /...
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I want to fake a 4-core machine when the physical machine only has 1 CPU core

I have only a 1 core CPU, but some programs need to see 4 CPUs to work correctly (although they will not use all of them). I am using Ubuntu and my CPU info looks like this ubuntu@z:~$ lscpu ...
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Why does cat /sys/devices/cpu/caps/pmu_name show something different than what lscpu shows?

I am currently working on a computer cluster and I wanted to see the architecture of the cpu. Running cat /sys/devices/cpu/caps/pmu_name shows [user@session]$ cat /sys/devices/cpu/caps/pmu_name ...
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Discrepancy between process affinity and actual core used

I try to use cpuset shield to give one CPU core to specific process. The shield is created like this: # cset shield --cpu=11 cset: --> activating shielding: cset: moving 1545 tasks from root into ...
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Process CPU greater than machine CPU in AWS instance in Linux

I have an AWS headless instance with following details: Processor - Intel(R) Xeon(R) CPU E5-2666 v3 @ 2.90GHz Installed Memory(RAM) - 60215 MB Physical Cores - 18 Logical Cores - 36 OS - CentOS Linux ...
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Count process L2 and L3 page faults (L3 thrashing and memory thrashing)

Right now I detect the problem by noticing that the process takes much longer than expected, killing the process and adjusting memory usage. The more time an algorithm takes the more time I waste, ...
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Relationship between RAM and CPU to assign to servers

I would like to know if there is any method, formula, recommendation or good practice to establish the relationship between CPU and RAM on a server, be it physical or virtual, I have recently seen ...
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IPSec multithreading via pcrypt worse than single thread

According to this document: https://www.strongswan.org/docs/Steffen_Klassert_Parallelizing_IPsec.pdf parallelizing IPSec using pcrypt kernel module will make the connection much more efficient (graphs ...
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Run windows driver for usb writing pad without vt-x

I want to use an old usb writing pad, which is a hiddev. My laptop's cpu (intel core 2 duo T5250) doesn't have vt-x. Can virt-manager or wine run the software/driver for windows? Can I use 32 bit ...
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Set CPU to high performance

I spent hours searching for an answer in Internet. All I could find doesn't help. I have Intel i9-9980HK, running under Ubuntu 20.04, kernel 5.4.0-33. The problem is that under the full load the CPU ...
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How to check how much CPU assigned to my VPS?

I have bought a VPS service that is claimed to give 4 cores wuth total 6GHz power. I have installed CentOS 8 on this VPS and want to check if I have that power of CPU or not? This is the info I do get ...
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cpu usage increase issus (network traffic is stable, no big difference)

I run a docker container (a node application), I found the host has CPU usage increasing issue. It goes from 0 to 60% in about 8~10 hours, then the application crash (https service, and get api ...
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pidstat %CPU vs htop %CPU of a process

I'm using the pidstat to monitor the cpu usage of a process and it shows 100%. For the same process the htop or top shows 200% for the same process. The system has 16 cores, and the process i am ...
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How to manually set CPU Fan Speed in Debian Linux?

As my CPU cooler fan broke on a setup with older hardware, I had to replace it with a similar fan, which unfortunately is pretty noisy. I am using the following system: Mainboard Gigabyte F2A88X-Up4 ...
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VirtualBox Win 7 Update Failed with Processor not Supported

It's a freshly created win 7 pro 32-bit vm on a VirtualBox. However the windows update only worked before the latest two. It gets "the processor is not supported together with the Windows version that ...
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Assign more cores to virtualbox

I have a Intel i5 processor (4 core), why am i not able to assign more than 2 cores to Centos 7 64 Bit in Virtualbox? Is there a limitation or i may be missing something ?
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Another Meltdown / Spectre Question [closed]

I recently tested using mitigations=off in my grub boot parameters, and found that my Celeron N4000 CPU on my thin and light laptop has almost doubled in performance! I can easily see the difference......
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Can I run 64 bit ubuntu on my pc (>10 years old)

I don't know anything about CPUs. I have a 32-bit version of ubuntu. But I need to install 64-bit applications. I came to know that it is not possible to run 64-bit apps on 32 bit OS. So I decided to ...
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Intel Turbo Boost State Resets On Boot

have an Intel(R) Core(TM) i7-8750H CPU on my Lenovo Ideapad 330-15ICH. After switching to Ubuntu 20.04 LTS, from Windows 10, I couldn't turn on the Turbo boost. After finding this solution everything ...
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What is section_type: general processor error

In my server, I saw this: BERT: Error records from previous boot: [Hardware Error]: event severity: fatal [Hardware Error]: Error 0, type: fatal [Hardware Error]: section_type: general processor ...
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How to run top for one iteration, -n flag not working

I am running top and only want a snapshot of the CPU usage values at the current moment so I tried using top -n 1 | grep "%CPU(s). However, top outputs the same exact values every single time I run it....
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Intel CPU stepping - naming convention

I'm having trouble enabling IOMMU on Centos 8 (4.18.0-147.8.1.el8_1.x86_64) and I'm starting to think that my CPU doesn't support VT-d. On the Intel ARK page for my CPU it says "yes" for VT-x and VT-...
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Trying to speed up lightweight distro on old computer

I'm trying to install a lightweight distro on my sister's old desktop. It has a Celeron 3.06Ghz processor, a 80GB HD but only 432 MiB RAM. With these specs I thought antiX-09.2.1_386-base was my best ...
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How does Linux accomplish pre-emptive scheduling?

I am reading up on Linux processes from The Linux Documentation Project: https://www.tldp.org/LDP/tlk/kernel/processes.html Processes are always making system calls and so may often need to wait. ...
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Why is the CPU (L1/L2) cache reported as 0kb in opensuse15.1?

When I use sudo dmidecode -t cache, I got this: Handle 0x0005, DMI type 7, 27 bytes Cache Information Socket Designation: L1 Cache Configuration: Enabled, Not Socketed, Level 1 ...
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Ubuntu server 50% of all cpu's 100% used. Unable to find the cause

I'm trying to find out why my server is showing 50% cpu in use to 100% while there is almost no activity on the server. and this is not so after each reboot. if I reboot the server then all is normal ...
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CPU throttling under low util when gaming; OK under 100% util when stress testing

I am on Ubuntu 19.10 (fresh install) with laptop ASUS G501J and I experience heavy lag when starting games. I first noticed this with Divinity Original Sin 2 under Proton. After some investigation I ...
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CPU Utilization history and what caused high load

I'm trying to find out what caused the cpu to run on 100% for 2 hours on 26th this month. Is there a way to find out what processes caused the high load? All i can find through sar is the cpu ...
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Changing the CPU affinity for all process from a user

I understand I can use taskset to change the CPU affinity of one process, but what if I want to change the CPU affinity of all processes run by a user at once?
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Why CPU temperature so much lower when on TLP Battery mode instead of AC mode?

I'm using Ubuntu 18.04 and TLP (Linux Advanced Power Management). When I have my laptop plugged and battery inserted and TLP is in auto mode (it detects the cable and goes AC mode), the CPU ...
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Single call to top shows low CPU usage

I am running a test to measure CPU load on a machine running debian. For the test I've made a simple Python script that overloads all CPUs. Now, when running top | grep Cpu(s), on the first call im ...
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CPU MHz don't reach CPU min MHz in lscpu

I think CPU MHZ is always more than CPU min MHz. But, my server can't do that now. When it looks like below, what should I check? Architecture: x86_64 CPU op-mode(s): 32-bit, 64-...
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Do I need CPU (or any) microcode in a QEMU/KVM virtual machine?

A CPU in a virtual machine is only virtual so I would assume that the microcode of the manufacturer does not need to be loaded. The same is probably valid for GPUs. Is this correct? Is there any ...
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renice and ionice processes that are hogging resources

I've noticed that Linux grids to a halt as soon as 1 application or 2 take up all the CPU or Disk IO resources. The best solution I've found so far is to renice the processes to idle, this is of ...
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In which context the linux block device driver request runs?

Finally, the invocation of the request function is (usually) entirely asynchronous with respect to the actions of any user-space process. You cannot assume that the kernel is running in the ...
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Increasing battery life on Linux

I got myself a new laptop, which is pretty powerful, but the battery life is horrible on both Windows and Linux. I was wondering if there is a way to increase battery life on Linux. I already tried ...

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